freeCodeCamp/challenges/basic-javascript.json

{
  "name": "Basic JavaScript",
  "order": 0.005,
  "challenges": [
    {
      "id":"bd7123c9c441eddfaeb4bdef",
      "title": "Comment your JavaScript Code",
      "difficulty":"9.98",
      "description":[
        "Comments are lines of code that your computer will intentionally ignore. Comments are a great way to leave notes to yourself and to other people who will later need to figure out what it does.",
        "Let's take a look at the two ways you can write comments in JavaScript.",
        "The double-slash comment will comment out the remainder of the text on the current line:",
        "<code>// This is a comment.</code>",
        "The slash-star-star-slash comment will comment out everything between the <code>/*</code> and the <code>*/</code> characters:",
        "<code>/* This is also a comment */</code>",
        "Try creating one of each."
      ],
      "tests":[
        "assert(editor.getValue().match(/(\\/\\/)...../g), 'Create a <code>\\/\\/</code> style comment that contains at least five letters');",
        "assert(editor.getValue().match(/(\\/\\*)...../g), 'Create a <code>\/\\* \\*\/</code> style comment that contains at least five letters.');",
        "assert(editor.getValue().match(/(\\*\\/)/g), 'Make sure that you close the comment with a <code>\\*\/</code>');"
      ],
      "challengeSeed":[
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c441eddfaeb5bdef",
      "title": "Understand Boolean Values",
      "difficulty": "9.98001",
      "description": [
        "In computer science, <code>data structures</code> are things that hold data. JavaScript has seven of these. For example, the <code>Number</code> data structure holds numbers.",
        "Let's learn about the most basic data structure of all: the <code>Boolean</code>. Booleans can only hold the value of either true or false. They are basically little on-off switches.",
        "Let's modify our <code>welcomeToBooleans</code>function so that it will return <code>true</code>instead of <code>false</code>when the run button is clicked."
      ],
      "tests": [
        "assert(typeof(welcomeToBooleans()) === 'boolean', 'The <code>welcomeToBooleans()</code> function should return a boolean &#40;true/false&#41; value.');",
        "assert(welcomeToBooleans() === true, '<code>welcomeToBooleans()</code> should return true.');"
      ],
      "challengeSeed": [
        "function welcomeToBooleans() {",
        "",
        "// don't change code above here",
        "",
        "  return false;",
        "",
        "// don't change code below here",
        "}",
        "",
        "welcomeToBooleans();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c443eddfaeb5bdef",
      "title": "Declare JavaScript Variables",
      "difficulty": "9.9801",
      "description": [
        "When we store data in a <code>data structure</code>, we call it a <code>variable</code>. These variables are no different from the x and y variables you use in math.",
        "Let's create our first variable and call it \"myName\".",
        "You'll notice that in <code>myName</code>, we didn't use a space, and that the \"N\" is capitalized. JavaScript variables are written in <code>camel case</code>. An example of camel case is: camelCase.",
        "Now, use the <code>var</code> keyword to create a variable called <code>myName</code>. Set its value to your name, in double quotes.",
        "Look at the <code>ourName</code> example if you get stuck."
      ],
      "tests": [
        "assert((function(){/**/if(typeof(myName) !== \"undefined\" && typeof(myName) === \"string\" && myName.length > 0){return(true);}else{return(false);}/**/})(), 'myName should be a string that contains at least one character in it');"
      ],
      "challengeSeed": [
        "// var ourName = \"Free Code Camp\";",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "",
        "if(typeof(myName) !== \"undefined\"){(function(v){return(v);})(myName);}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c444eddfaeb5bdef",
      "title": "Declare String Variables",
      "difficulty": "9.9802",
      "description": [
        "In the previous challenge, we used the code <code>var myName = \"your name\"</code>. This is what we call a <code>String</code> variable. It is nothing more than a \"string\" of characters. JavaScript strings are always wrapped in quotes.",
        "Now let's create two new string variables: <code>myFirstName</code>and <code>myLastName</code> and assign them the values of your first and last name, respectively."
      ],
      "tests": [
        "assert((function(){if(typeof(myFirstName) !== \"undefined\" && typeof(myFirstName) === \"string\" && myFirstName.length > 0){return(true);}else{return(false);}})(), 'myFirstName should be a string with a least one character in it');",
        "assert((function(){if(typeof(myLastName) !== \"undefined\" && typeof(myLastName) === \"string\" && myLastName.length > 0){return(true);}else{return(false);}})(), 'myLastName should be a string with a least one character in it');"
      ],
      "challengeSeed": [
        "// name = \"Alan Turing\";",
        "// var firstName = \"Alan\";",
        "// var lastName = \"Turing\";",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(myFirstName) !== \"undefined\" && typeof(myLastName) !== \"undefined\"){(function(){return(myFirstName + ', ' + myLastName);})();}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c448eddfaeb5bdef",
      "title": "Check the Length Property of a String Variable",
      "difficulty": "9.9809",
      "description": [
        "<code>data structures</code> have <code>properties</code>. For example, <code>strings</code> have a property called <code>.length</code> that will tell you how many characters are in the string.",
        "For example, if we created a variable <code>var firstName = \"Charles\"</code>, we could find out how long the string \"Charles\" is by using the <code>firstName.length</code> property.",
        "Use the <code>.length</code> property to count the number of characters in the <code>lastNameLength</code> variable."
      ],
      "tests": [
        "assert((function(){if(typeof(lastNameLength) !== \"undefined\" && typeof(lastNameLength) === \"number\" && lastNameLength === 8){return(true);}else{return(false);}})(), 'lastNameLength should be equal to eight.');",
        "assert((function(){if(editor.getValue().match(/\\.length/gi) && editor.getValue().match(/\\.length/gi).length >= 2 && editor.getValue().match(/var lastNameLength \\= 0;/gi) && editor.getValue().match(/var lastNameLength \\= 0;/gi).length >= 1){return(true);}else{return(false);}})(), 'You should be getting the length of <code>lastName</code> by using <code>.length</code> like this: <code>lastName.length</code>');"
      ],
      "challengeSeed": [
        "var firstNameLength = 0;",
        "var lastNameLength = 0;",
        "var firstName = \"Ada\";",
        "",
        "firstNameLength = firstName.length;",
        "",
        "var lastName = \"Lovelace\";",
        "",
        "lastNameLength = lastName;",
        "",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(lastNameLength) !== \"undefined\"){(function(){return(lastNameLength);})();}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c549eddfaeb5bdef",
      "title": "Use Bracket Notation to Find the First Character in a String",
      "difficulty": "9.9810",
      "description": [
        "<code>Bracket notation</code> is a way to get a character at a specific <code>index</code> within a string.",
        "Computers don't start counting at 1 like humans do. They start at 0.",
        "For example, the character at index 0 in the word \"Charles\" is \"C\". So if <code>var firstName = \"Charles\"</code>, you can get the value of the first letter of the string by using <code>firstName[0]</code>.",
        "Use <code>bracket notation</code> to find the first character in a the <code>firstLetterOfLastName</code> variable.",
        "Try looking at the <code>firstLetterOfFirstName</code> variable declaration if you get stuck."
      ],
      "tests": [
        "assert((function(){if(typeof(firstLetterOfLastName) !== \"undefined\" && editor.getValue().match(/\\[0\\]/gi) && typeof(firstLetterOfLastName) === \"string\" && firstLetterOfLastName === \"L\"){return(true);}else{return(false);}})(), 'The first letter of firstLetterOfLastName should be a L');"
      ],
      "challengeSeed": [
        "var firstLetterOfLastName = \"\";",
        "var firstLetterOfLastName = \"\";",
        "",
        "var firstName = \"Ada\";",
        "",
        "firstLetterOfFirstName = firstName[0];",
        "",
        "var lastName = \"Lovelace\";",
        "",
        "firstLetterOfLastName = lastName;",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(v){return(v);})(firstLetterOfLastName);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c450eddfaeb5bdef",
      "title": "Use Bracket Notation to Find the Nth Character in a String",
      "difficulty": "9.9811",
      "description": [
        "You can also use <code>bracket Notation</code>to get the character at other positions within a string.",
        "Remember that computers start counting at 0, so the first character is actually the zeroth character.",
        "Let's try to set <code>thirdLetterOfLastName</code>to equal the <code>third letter</code> of the <code>lastName</code> variable.",
        "Try looking at the <code>secondLetterOfFirstName</code> variable declaration if you get stuck."
      ],
      "tests": [
        "assert(thirdLetterOfLastName === 'v', 'The third last letter of lastName should be a \"v\"');"
      ],
      "challengeSeed": [
        "var firstName = \"Ada\";",
        "",
        "var secondLetterOfFirstName = firstName[1];",
        "",
        "var lastName = \"Lovelace\";",
        "",
        "var thirdLetterOfLastName = lastName;",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(v){return(v);})(thirdLetterOfLastName);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c451eddfaeb5bdef",
      "title": "Use Bracket Notation to Find the Last Character in a String",
      "difficulty": "9.9812",
      "description": [
        "In order to get the last letter of a string, you can subtract one from the string's length.",
        "For example, if <code>var firstName = \"Charles\"</code>, you can get the value of the last letter of the string by using <code>firstName[firstName.length - 1]</code>.",
        "Use <code>bracket notation</code> to find the last character in the <code>lastName</code> variable.",
        "Try looking at the <code>lastLetterOfLastName</code> variable declaration if you get stuck."
      ],
      "tests": [
        "assert(lastLetterOfLastName === \"e\", 'lastLetterOfLastName should be \"e\"');",
        "assert(editor.getValue().match(/\\.length/g), 'You have to use <code>.length</code> to get the last letter');"
      ],
      "challengeSeed": [
        "var firstName = \"Ada\";",
        "",
        "var lastLetterOfFirstName = firstName[firstName.length - 1];",
        "",
        "var lastName = \"Lovelace\";",
        "",
        "var lastLetterOfLastName = lastName;",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(v){return(v);})(lastLetterOfLastName);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7123c9c452eddfaeb5bdef",
      "title": "Use Bracket Notation to Find the Nth-to-Last Character in a String",
      "difficulty": "9.9813",
      "description": [
        "In order to get the last letter of a string, you can subtract one from the string's length.",
        "For example, you can get the value of the third-to-last letter of the <code>var firstName = \"Charles\"</code> string by using <code>firstName[firstName.length - 3]</code>.",
        "Use <code>bracket notation</code> to find the second-to-last character in the <code>lastName</code> string.",
        "Try looking at the <code>lastLetterOfLastName</code> variable declaration if you get stuck."
      ],
      "tests": [
        "assert(secondToLastLetterOfLastName === 'c', 'secondToLastLetterOfLastName should be \"c\".');",
        "assert(editor.getValue().match(/\\.length/g), 'You have to use .length to get the third last letter.');"
      ],
      "challengeSeed": [
        "var firstName = \"Ada\";",
        "",
        "var thirdToLastLetterOfFirstName = firstName[firstName.length - 3];",
        "",
        "var lastName = \"Lovelace\";",
        "",
        "var secondToLastLetterOfLastName = lastName;",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(v){return(v);})(secondToLastLetterOfLastName);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "cf1111c1c11feddfaeb3bdef",
      "title": "Add Two Numbers with JavaScript",
      "difficulty": "9.98141",
      "description": [
        "Let's try to add two numbers using JavaScript.",
        "JavaScript uses the <code>+</code> symbol for addition.",
        "Replace the <code>0</code> with the correct number so you can get the result mentioned in the comment."
      ],
      "tests": [
        "assert((function(){if(sum === 20 && editor.getValue().match(/\\+/g)){return(true);}else{return(false);}})(), 'Make the variable <code>sum</code> equal 20');"
      ],
      "challengeSeed": [
        "var sum = 10 + 0; //make this equal to 20 by changing the 0 into the appropriate number.",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return('sum='+z);})(sum);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "cf1111c1c11feddfaeb4bdef",
      "title": "Subtract One Number from Another with JavaScript",
      "difficulty": "9.98142",
      "description": [
        "We can also subtract one number from another.",
        "JavaScript uses use the <code>-</code> symbol for subtraction.",
        "Replace the <code>0</code> with the correct number so you can get the result mentioned in the comment."
      ],
      "tests": [
        "assert((function(){if(difference === 12 && editor.getValue().match(/\\-/g)){return(true);}else{return(false);}})(), 'Make the variable <code>difference</code> equal 12');"
      ],
      "challengeSeed": [
        "var difference = 45 - 0; //make this equal to 12 by changing the 0 into the appropriate number.",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return('difference='+z);})(difference);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "cf1231c1c11feddfaeb5bdef",
      "title": "Multiply Two Numbers with JavaScript",
      "difficulty": "9.98143",
      "description": [
        "We can also multiply one number by another.",
        "JavaScript uses use the <code>*</code> symbol for multiplication.",
        "Replace the <code>0</code> with the correct number so you can get the result mentioned in the comment."
      ],
      "tests": [
        "assert((function(){if(product === 80 && editor.getValue().match(/\\*/g)){return(true);}else{return(false);}})(), 'Make the variable <code>product</code> equal 80.');"
      ],
      "challengeSeed": [
        "var product = 8 * 0; //make this equal to 80 by changing the 0 into the appropriate number.",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return('product='+z);})(product)"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "cf1111c1c11feddfaeb6bdef",
      "title": "Divide One Number by Another with JavaScript",
      "difficulty": "9.9814",
      "description": [
        "We can also divide one number by another.",
        "JavaScript uses use the <code>/</code> symbol for division.",
        "Replace the <code>0</code> with the correct number so you can get the result mentioned in the comment."
      ],
      "tests": [
        "assert((function(){if(quotient === 2 && editor.getValue().match(/\\//g)){return(true);}else{return(false);}})(), 'Make the variable <code>quotient</code> equal 2.');"
      ],
      "challengeSeed": [
        "var quotient = 66 / 0; //make this equal to 2 by changing the 0 into the appropriate number.",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return('quotient='+z);})(quotient);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "cf1391c1c11feddfaeb4bdef",
      "title": "Create Decimal Numbers with JavaScript",
      "difficulty": "9.9815",
      "description": [
        "JavaScript number variables can also have decimals.",
        "Let's create a variable <code>myDecimal</code> and give it a decimal value."
      ],
      "tests": [
        "assert((function(){if(typeof(myDecimal) !== \"undefined\" && typeof(myDecimal) === \"number\" && editor.getValue().match(/\\./g).length >=2){return(true);}else{return(false);}})(), 'myDecimal should be a decimal point number.');"
      ],
      "challengeSeed": [
        "// var ourDecimal = 5.7;",
        "// Create a number with a decimal point here called myDecimal",
        "",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(){if(typeof(myDecimal) !== \"undefined\"){return(myDecimal);}})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7993c9c69feddfaeb7bdef",
      "title": "Perform Arithmetic Operations on Decimals with JavaScript",
      "difficulty": "9.98151",
      "description": [
        "In JavaScript, you can also perform calculations with decimal numbers, just like whole numbers.",
        "Replace the <code>0.0</code> with the correct number so that you get the result mentioned in the comments."
      ],
      "tests": [
        "assert((function(){if(product === 5.0 && editor.getValue().match(/\\*/g)){return(true);}else{return(false);}})(), 'Make the variable <code>product</code> equal 5.0.');"
      ],
      "challengeSeed": [
        "var quotient = 4.4 / 2.0; // equals 2.2",
        "var product = 2.0 * 0.0; // equals 5.0",
        "",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(y){return('product='+y);})(product);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bd7993c9c69feddfaeb8bdef",
      "title": "Store Multiple Values in one Variable using JavaScript Arrays",
      "difficulty": "9.9816",
      "description": [
        "With JavaScript <code>array</code> variables, we can store several pieces of data in one place.",
        "You start an array declaration with an opening bracket, end it with a closing bracket, and put a comma between each entry, like this: <code>var sandwich = [\"peanut butter\", \"jelly\", \"bread\"]</code>.",
        "Now let's create a new array called <code>myArray</code> that contains both a <code>string</code> and a <code>number</code>.",
        "Refer to the comments if you get stuck."
      ],
      "tests": [
        "assert(typeof(myArray) == 'object', 'myArray should be an array');",
        "assert(typeof(myArray[0]) !== 'undefined' && typeof(myArray[0]) == 'string', 'The first item in myArray should be a string');",
        "assert(typeof(myArray[1]) !== 'undefined' && typeof(myArray[1]) == 'number', 'The second item in myArray should be a number');"
      ],
      "challengeSeed": [
        "//var array = [\"John\", 23];",
        "",
        "var myArray = [];",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return(z);})(myArray);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c11feddfaeb7bdef",
      "title": "Nest one Array within Another Array",
      "difficulty":"9.98161",
      "description":[
        "You can also nest arrays within other arrays, like this: <code>[[\"Bulls\", 43]]</code>.",
        "Let's now go create a nested array called <code>myArray</code>."
      ],
      "tests":[
        "assert((function(){if(typeof(myArray) !== \"undefined\" && typeof(myArray) === \"object\" && typeof(myArray[0]) !== \"undefined\" && typeof(myArray[0]) === \"object\" && editor.getValue().match(/\\[\\s?\\[/g).length >= 1 && editor.getValue().match(/\\]\\s?\\]/g).length >= 1){return(true);}else{return(false);}})(), 'myArray should contain at least one array');"
      ],
      "challengeSeed":[
        "var ourArray = [[\"the universe\", \"everything\", 42]];",
        "var myArray = [];",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(myArray) !== \"undefined\"){(function(){return(myArray);})();}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"bg9997c9c79feddfaeb9bdef",
      "title": "Access Array Data with Indexes",
      "difficulty":"9.9817",
      "description":[
        "We can access the data inside arrays using <code>indexes</code>.",
        "Array indexes are written in the same bracket notation that strings use, except that instead of specifying a character, they are specifying an entry in the array.",
        "For example:",
        "<code>var array = [1,2,3];</code>",
        "<code>array[0]; //equals 1</code>",
        "<code>var data = array[1];</code>",
        "Create a variable called <code>myData</code> and set it to equal the first value of <code>myArray</code>."
      ],
      "tests":[
        "assert((function(){if(typeof(myArray) != 'undefined' && typeof(myData) != 'undefined' && myArray[0] == myData){return(true);}else{return(false);}})(), 'The variable <code>myData</code> should equal the first value of myArray');"
      ],
      "challengeSeed":[
        "//var ourArray = [1,2,3];",
        "//var ourData = ourArray[0]; // equals 1",
        "",
        "var myArray = [1,2,3];",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(myArray) !== \"undefined\" && typeof(data) !== \"undefined\"){(function(y,z){return('myArray = ' + JSON.stringify(y) + ', data = ' + JSON.stringify(z));})(myArray, data);}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c11feddfaeb8bdef",
      "title": "Modify Array Data With Indexes",
      "difficulty":"9.98171",
      "description":[
        "We can also modify the data stored in arrays by using indexes.",
        "For example:",
        "<code>var ourArray = [3,2,1];</code>",
        "<code>ourArray[0] = 1; // equals [1,2,1]</code>",
        "Now modify the data stored at index 0 of <code>myArray</code> to the value of 3."
      ],
      "tests":[
        "assert((function(){if(typeof(myArray) != 'undefined' && myArray[0] == 3 && myArray[1] == 2 && myArray[2] == 3){return(true);}else{return(false);}})(), 'myArray should now be [3,2,3]');",
        "assert((function(){if(editor.getValue().match(/[0]/g).length >= 2 && editor.getValue().match(/=/g).length >= 2){return(true);}else{return(false);}})(), 'You should be using indexes to modify the values in myArray');"
      ],
      "challengeSeed":[
        "var ourArray = [1,2,3];",
        "ourArray[1] = 3;",
        "// ourArray[1] now equals [1,3,3].",
        "var myArray = [1,2,3];",
        "",
        "",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(myArray) !== \"undefined\"){(function(){return(myArray);})();}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bg9994c9c69feddfaeb9bdef",
      "title": "Manipulate Arrays With pop()",
      "difficulty": "9.9818",
      "description": [
        "Another way to change the data in an array is with the <code>.pop()</code> function.",
        "<code>.pop()</code>is used to \"pop\" a value off of the end of an array. We can retrieve this value by performing <code>pop()</code> in a variable declaration.",
        "Any type of variable can be \"popped\" off of an array.",
        "Use the <code>.pop()</code> function to remove the last item from myArray."
      ],
      "tests": [
        "assert((function(d){if(d[0] == 'John' && d[1] == 23 && d[2] == undefined){return(true);}else{return(false);}})(myArray), 'myArray should only have the first two values left([\"John\", 23])');",
        "assert((function(d){if(d[0] == 'cat' && d[1] == 2 && d[2] == undefined){return(true);}else{return(false);}})(removed), 'myArray should only have the first two values left([\"cat\"], 2)');"
      ],
      "challengeSeed": [
        "//var numbers = [1,2,3];",
        "//console.log(numbers); // logs [1,2,3]",
        "//var removed = numbers.pop();",
        "//console.log(numbers); // logs [1,2]",
        "//console.log(removed); // logs 3",
        "",
        "var myArray = [\"John\", 23, [\"cat\", 2]];",
        "var removed = myArray; // This should be [\"cat\", 2] and myArray should now be [\"John\", 23]",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(y, z){return('myArray = ' + JSON.stringify(y) + ' & removed = ' + JSON.stringify(z));})(myArray, removed);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bg9995c9c69feddfaeb9bdef",
      "title": "Manipulate Arrays With push()",
      "difficulty": "9.9818",
      "description": [
        "Not only can you <code>pop()</code> data off of the end of an array, you can also <code>push()</code> data onto the end of an array.",
        "Take the myArray array and <code>push()</code> this value to the end of it: <code>[\"dog\", 3]</code>."
      ],
      "tests": [
        "assert((function(d){if(d[2] != undefined && d[0] == 'John' && d[1] == 23 && d[2][0] == 'dog' && d[2][1] == 3 && d[2].length == 2){return(true);}else{return(false);}})(myArray), 'myArray should only have the first two values left([\"John\", 23, [\"dog\", 3]])');"
      ],
      "challengeSeed": [
        "var ourArray = [\"Stimpson\", \"J\", [\"cat\"]];",
        "ourArray.pop();",
        "ourArray.push([\"happy\", \"joy\"]);",
        "// ourArray now equals [\"Stimpson\", \"J\", [\"happy\", \"joy\"]]",
        "",
        "var myArray = [\"John\", 23, [\"cat\", 2]];",
        "myArray.pop();",
        "//Add a [\"dog\", 3] to the end of myArray using push()",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(z){return('myArray = ' + JSON.stringify(z));})(myArray);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bg9996c9c69feddfaeb9bdef",
      "title": "Manipulate Arrays With shift()",
      "difficulty": "9.9817",
      "description": [
        "<code>pop()</code> always removes the last element of an array. What if you want to remove the first? That's where <code>.shift()</code> comes in.",
        "Take the myArray array and <code>shift()</code> the first value off of it."
      ],
      "tests": [
        "assert((function(d){if(d[0] == 23 && d[1][0] == 'dog' && d[1][1] == 3 && d[2] == undefined){return(true);}else{return(false);}})(myArray), 'myArray should only have the first two values left([\"John\", 23])');",
        "assert((function(d){if(d === 'John' && typeof(myRemoved) === 'string'){return(true);}else{return(false);}})(myRemoved), 'myRemoved should contain \"John\"');"
      ],
      "challengeSeed": [
        "var ourArray = [\"Stimpson\", \"J\", [\"cat\"]];",
        "ourRemoved = ourArray.shift();",
        "// ourArray now equals [\"J\", [\"cat\"]]",
        "",
        "var myArray = [\"John\", 23, [\"dog\", 3]];",
        "var myRemoved = myArray; // This should be [\"John\"] and myArray should now be [23, [\"dog\", 3]]",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(y, z){return('myArray = ' + JSON.stringify(y) + ' & myRemoved = ' + JSON.stringify(z));})(myArray, myRemoved);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id": "bg9997c9c69feddfaeb9bdef",
      "title": "Manipulate Arrays With unshift()",
      "difficulty": "9.9818",
      "description": [
        "Now that we've learned how to <code>shift</code>things from the start of the array, we need to learn how to <code>unshift</code>stuff back to the start",
        "Let's take the code we had last time and <code>unshift</code>this value to the end: <code>\"Paul\" </code>"
      ],
      "tests": [
        "assert((function(d){if(d[0].toLowerCase() == 'paul' && d[1] == 23 && d[2][0] != undefined && d[2][0] == 'dog' && d[2][1] != undefined && d[2][1] == 3){return(true);}else{return(false);}})(myArray), 'myArray should now have [\"Paul\", 23, [\"dog\", 3]])');"
      ],
      "challengeSeed": [
        "var ourArray = [\"Stimpson\", \"J\", [\"cat\"]];",
        "ourArray.shift();",
        "ourArray.unshift([\"happy\", \"joy\"]);",
        "// ourArray now equals [[\"happy\", \"joy\"], \"Stimpson\", \"J\"]",
        "",
        "var myArray = [\"John\", 23, [\"dog\", 3]];",
        "myArray.shift();",
        "// Add \"Paul\" to the start of myArray",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "(function(y, z){return('myArray = ' + JSON.stringify(y));})(myArray);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"bg9997c9c89feddfaeb9bdef",
      "title": "Write Reusable JavaScript with Functions",
      "difficulty":"9.9819",
      "description":[
        "In JavaScript, we can divide up our code into reusable parts called <code>functions</code>.",
        "Here's an example of a function:",
        "<code>function functionName (a, b) {</code>",
        "<code>&thinsp;&thinsp;return(a + b);</code>",
        "<code>}</code>",
        "We can \"call\" our function like this: <code>functionName();</code>, and it will run and return it's <code>return</code> value to us.",
        "Create and call a function called <code>myFunction</code>."
      ],
      "tests":[
        "assert((function(){if(typeof(f) !== \"undefined\" && typeof(f) === \"number\" && f === a + b  && editor.getValue().match(/return/gi).length >= 1 && editor.getValue().match(/a/gi).length >= 1 && editor.getValue().match(/b/gi).length >= 1 && editor.getValue().match(/\\+/gi).length >= 1){return(true);}else{return(false);}})(), 'Your function should return the value of a + b');"
      ],
      "challengeSeed":[
        "var a = 4;",
        "var b = 5;",
        "",
        "ourFunction = function() {",
        "  return a - b;",
        "};",
        "",
        "//Don't modify above this line",
        "//Create a function called myFunction that returns the value of a plus b.",
        "",
        "",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "// You'll learn about functions soon.",
        "if(typeof(myFunction) !== \"undefined\"){",
        "var f=myFunction(a,b);",
        "(function(){return(f);})();",
        "}"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"bg9998c9c99feddfaeb9bdef",
      "title": "Build JavaScript Objects",
      "difficulty":"9.9822",
      "description":[
        "You may have heard the term <code>object</code> before.",
        "Objects are similar to <code>arrays</code>, except that instead of using indexes to access and modify their data, you access the data in objects through what are called <code>properties</code>.",
        "Here's a sample object:",
        "<code>var cat = {</code>",
        "<code>  \"name\": \"Whiskers\",</code>",
        "<code>  \"legs\": 4,</code>",
        "<code>  \"tails\": 1,</code>",
        "<code>  \"enemies\": [\"Water\", \"Dogs\"]</code>",
        "<code>};</code>",
        "</code>",
        "Objects are useful for storing data in a structured way, and can represents real world objects, like a cats.",
        "Let's try to make an Object that represents a dog called myDog!"
      ],
      "tests":[
        "assert((function(z){if(z.hasOwnProperty(\"name\") && z.name !== undefined && typeof(z.name) === \"string\"){return(true);}else{return(false);}})(myDog), 'myDog should contain the property name and it should be a string');",
        "assert((function(z){if(z.hasOwnProperty(\"legs\") && z.legs !== undefined && typeof(z.legs) === \"number\"){return(true);}else{return(false);}})(myDog), 'myDog should contain the property legs and it should be a number');",
        "assert((function(z){if(z.hasOwnProperty(\"tails\") && z.tails !== undefined && typeof(z.tails) === \"number\"){return(true);}else{return(false);}})(myDog), 'myDog should contain the property tails and it should be a number');",
        "assert((function(z){if(z.hasOwnProperty(\"friends\") && z.friends !== undefined && Array.isArray(z.friends)){return(true);}else{return(false);}})(myDog), 'myDog should contain the property friends and it should be an array');"
      ],
      "challengeSeed":[
        "//var ourDog = {",
        "//   \"name\": \"Camper\"",
        "//   \"legs\": 4",
        "//   \"tails\": 1",
        "//   \"friends\": [\"everything!\"]",
        "//};",
        "",
        "// add the name(string), legs(number), tails(number) and friends(array) properties to myDog.",
        "// You can set them to whatever you want.",
        "",
        "var myDog = {",
        "   ",
        "};",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(z){return(z);})(myDog);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"bg9999c9c99feddfaeb9bdef",
      "title": "Manipulate JavaScript Objects",
      "difficulty":"9.9823",
      "description":[
        "There are many ways to add and add and remove properties from objects.",
        "For example, we can add properties to objects like this:",
        "<code>myObject.myProperty = \"myValue\";</code>",
        "We can also delete them like this:",
        "<code>delete(myObject.myProperty);</code>",
        "Let's add the property \"bark\", and delete the property \"tails\"."
      ],
      "tests":[
        "assert(myDog.bark !== undefined, 'Add the property \"bark\" to myDog.');",
        "assert(myDog.tails === undefined, 'Delete the property \"tails\" from myDog.');"
      ],
      "challengeSeed":[
        "// var ourDog = {",
        "//   \"name\": \"Camper\"",
        "//   \"legs\": 4",
        "//   \"tails\": 1",
        "//   \"friends\": [\"everything!\"]",
        "// };",
        "",
        "// ourDog.bark(\"arf!\");",
        "// delete(ourDog.tails);",
        "",
        "var myDog = {",
        "   \"name\": \"Camper\",",
        "   \"legs\": 4,",
        "   \"tails\": 1,",
        "   \"friends\": []",
        "};",
        "// Don't change any code above this line.",
        "",
        "// Let's add the property bark to myDog",
        "",
        "",
        "// Now delete the property tails",
        "",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(z){return(z);})(myDog);"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c11feddfaeb5bdef",
      "title": "Iterate with JavaScript For Loops",
      "difficulty":"9.9824",
      "description":[
        "You can run the same code multiple times by using a loop.",
        "The most common type of JavaScript loop is called a \"for loop\" because it runs \"for\" a specific number of times.",
        "<code>var ourArray = [];</code>",
        "<code>for(var i = 0; i < 5; i++) {</code>",
        "<code>&thinsp;&thinsp;ourArray.push(i);</code>",
        "<code>}</code>",
        "<code>ourArray</code> will now contain [0,1,2,3,4] ",
        "Let's try getting a for loop to work by pushing values to an array."
      ],
      "tests":[
        "assert(editor.getValue().match(/for/g), 'You should be using a for loop for this.');",
        "assert.deepEqual(myArray, [0,1,2,3,4], 'myArray should equal [0,1,2,3,4]');"
      ],
      "challengeSeed":[
        "var myArray = [];",
        "//Push the numbers zero through four to myArray using a \"for loop\" like above.",
        "",
        ""
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c11feddfaeb1bdef",
      "title": "Iterate with JavaScript While Loops",
      "difficulty":"9.9825",
      "description":[
        "You can run the same code multiple times by using a loop.",
        "Another type of JavaScript loop is called a \"while loop\" because it runs \"while\" something is true, and stops once that something is no longer true.",
        "<code>var ourArray = [];</code>",
        "<code>var i = 0;</code>",
        "<code>while(i < 5) {</code>",
        "<code>&thinsp;&thinsp;ourArray.push(i);</code>",
        "<code>&thinsp;&thinsp;i++;</code>",
        "<code>}</code>",
        "Let's try getting a for loop to work by pushing values to an array."
      ],
      "tests":[
        "assert(editor.getValue().match(/while/g), 'You should be using a while loop for this.');",
        "assert.deepEqual(myArray, [0,1,2,3,4], 'myArray should equal [0,1,2,3,4]');"
      ],
      "challengeSeed":[
        "var myArray = [];",
        "//Push the numbers zero through four to myArray",
        "",
        ""
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c11feddfaeb9bdef",
      "title": "Generate Random Fractions with JavaScript",
      "difficulty":"9.9827",
      "description":[
        "Random numbers are useful for creating random behaviours and games.",
        "JavaScript has a <code>Math.random()</code> function that generates a random decimal number.",
        "Use <code>Math.random()</code> to get <code>myFunction</code> to return a random number."
      ],
      "tests":[
        "assert(typeof(myFunction()) === \"number\", 'myFunction should return a random number');",
        "assert((myFunction()+''). match(/\\./g), 'The number returned by myFunction should be a decimal');",
        "assert(editor.getValue().match(/Math\\.random/g).length >= 2, 'You should be using Math.random to generate the random decimal number');"
      ],
      "challengeSeed":[
        "function myFunction() {",
        "  //Change the 0 to Math.random()",
        "  return(0);",
        "}",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(){return(myFunction());})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb1bdef",
      "title": "Generate Random Whole Numbers with JavaScript",
      "difficulty":"9.9828",
      "description":[
        "It's great that we can create random decimal numbers, but it's even more useful if we lot more useful to generate a random whole number.",
        "To achieve this we can multiply the random number by ten and use the <code>Math.floor()</code> to convert the decimal number to a whole number",
        "This technique gives us a whole number between zero and nine",
        "Example:",
        "<code>Math.floor(Math.random()*10);</code>",
        "Let's give this technique a go now"
      ],
      "tests":[
        "assert(typeof(myFunction()) === \"number\", 'The result of myFunction should be a number');",
        "assert(editor.getValue().match(/Math.random/g), 'You should be using Math.random to create a random number');",
        "assert(!(''+myFunction()).match(/\\./g), 'You should have multiplied the result of Math.random but 10 to make it a number that\\'s greater then zero');",
        "assert(editor.getValue().match(/Math.floor/g), 'You should use Math.floor to remove the decimal part of the number');"
      ],
      "challengeSeed":[
        "function myFunction(){",
        "  // Make myFunction return a random number between zero and nine instead of a decimal",
        "  return(Math.random());",
        "}",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(){return(myFunction());})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb2bdef",
      "title": "Generate Random Whole Numbers within a Range",
      "difficulty":"9.9829",
      "description":[
        "We can use a certain mathematical expression to get a random number between between two numbers.",
        "<code>Math.floor(Math.random() * (max - min + 1)) + min</code>",
        "By using this we can control the output of a random number."
      ],
      "tests":[
        "assert(myFunction() >= min, 'The random number that\\'s generated by myFunction should be greater than or equal to the minimum number');",
        "assert(myFunction() <= max, 'The random number that\\'s generated by myFunction should be less than or equal to the maximum number');",
        "assert((function(){if(editor.getValue().match(/max/g).length >= 2 && editor.getValue().match(/min/g).length >= 2 && editor.getValue().match(/Math.floor/g) && editor.getValue().match(/Math.random/g)){return(true);}else{return(false);}})(), 'You should be using the function given in the description to calculate the random in number in a range');"
      ],
      "challengeSeed":[
        "var min = 0;",
        "var max = 12;",
        "function myFunction() {",
        "  // Make myFunction return a random number between zero and nine instead of a decimal",
        "  return(Math.random());",
        "}",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(){return(myFunction());})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb3bdef",
      "title": "Use Conditional Logic with If-Else Statements",
      "difficulty":"9.983",
      "description":[
        "We can use if statements in JavaScript to only execute code if a certain condition is met.",
        "if statements require some sort of boolean condition evaluate.",
        "Example:",
        "<code> if (1 == 2) {",
        "<code>&thinsp;&thinsp;return(true);</code>",
        "<code>}</code>",
        "<code>else {</code>",
        "<code>&thinsp;&thinsp;return(false);</code>",
        "<code>}</code>",
        "Let's use <code>if</code> and <code>else</code> statements to make a coin-flip game.",
        "Create an <code>if-else statement</code> to return <code>heads</code> if the flip var is zero and to return <code>tails</code> if it's not."
      ],
      "tests":[
        "assert((function(){if(myFunction() === \"heads\" || myFunction() === \"tails\"){return(true);}else{return(false);}})(), 'myFunction should either return heads or tails');",
        "assert(editor.getValue().match(/if/g).length >= 3, 'You should have created a new if statement');",
        "assert(editor.getValue().match(/else/g).length >= 2, 'You should have created a new else statement');"
      ],
      "challengeSeed":[
        "function myFunction(){",
        "  var flip = Math.floor(Math.random() * (1 - 0 + 1)) + 0;",
        "  // Create and if else statement here to return \"heads\" if flip is 0. Otherwise return \"tails\".",
        "",
        "}",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        "(function(){return(myFunction());})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb6bdef",
      "title": "Sift through Text with Regular Expressions",
      "difficulty":"9.984",
      "description":[
        "RegEx is a powerful tool we can use to find certain words or patterns in strings.",
        "RegEx can look difficult at first but there's not much to getting it working.",
        "If we wanted to find the number of times the word <code>the</code> occurred in the string <code>The dog chased the cat</code> We could use the following RegEx:",
        "<code>\/the+\/gi</code>",
        "Let's break this down a bit:",
        "<code>the</code> is the pattern we want to match.",
        "<code>+</code> means we are looking for one or more occurrences of this pattern.",
        "<code>g</code> means that it searches the entire string.",
        "<code>i</code> means that we are ignoring the case (uppercase or lowercase) of what we are looking for.",
        "Let's try finding the word and in the string <code>John and Alan went to the shop and got some milk</code> by replacing the <code>.+</code> in the current RegEx with something that will find the word <code>and</code> and count how many times it occurs."
      ],
      "tests":[
        "assert(test==2, 'Your <code>regular expression</code> should have found two occurrences of the word <code>and</code>');",
        "assert(editor.getValue().match(/\\/and\\+\\/gi/), 'You should have used <code>regular expressions</code> to find the word <code>and</code>');"
      ],
      "challengeSeed":[
        "var test = (function() {",
        "  var testString = \"John and Alan went to the shop and got some milk\";",
        "",
        "  //Do not modify above this line.",
        "",
        "  var expression = /.+/gi;",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        " return(testString.match(expression).length);",
        "})();(function(){return(test);})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb7bdef",
      "title": "Find Numbers with Regular Expressions",
      "difficulty":"9.985",
      "description":[
        "We can use special selectors in RegEx to select a particular type of value.",
        "One such selector is the digit selector <code>\\d</code> which is used to grab the numbers in a string.",
        "It is used like this:",
        "<code>/\\d+/g</code>"
      ],
      "tests":[
        "assert(test === 2, 'Your RegEx should have found two numbers in the testString');",
        "assert(editor.getValue().match(/\\/\\\\d\\+\\//gi), 'You should be using the following expression /\\d+/gi to find the numbers in the testString');"
      ],
      "challengeSeed":[
        "var test = (function() {",
        "  var testString = \"There's 3 cats but 4 dogs.\"",
        "",
        "//Do Not Modify Above",
        "",
        "  var expression = /.+/gi;",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        " return(testString.match(expression).length);",
        "})();(function(){return(test);})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c12feddfaeb8bdef",
      "title": "Find White Space with Regular Expressions",
      "difficulty":"9.986",
      "description":[
        "We can also use selectors like <code>\\s</code> to find spaces in a string.",
        "It is used like this:",
        "<code>/\\s+/g</code>"
      ],
      "tests":[
        "assert(test === 7, 'Your RegEx should have found seven spaces in the <code>testString</code>.');",
        "assert(editor.getValue().match(/\\/\\\\s\\+\\//gi), 'You should be using the following expression /\\s+/gi to find the spaces in the <code>testString</code>.');"
      ],
      "challengeSeed":[
        "var test = (function(){",
        "  var testString = \"How many spaces are there in this sentence.\";",
        "",
        "  // Do not modify the code above this line.",
        "",
        "  var expression = /.+/gi;",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        " return(testString.match(expression).length);",
        "})();(function(){return(test);})();"
      ],
      "type": "waypoint",
      "challengeType": 1
    },
    {
      "id":"cf1111c1c13feddfaeb3bdef",
      "title": "Invert Regular Expression Matches with JavaScript",
      "difficulty":"9.987",
      "description":[
        "Use <code>/\\S/gi;</code> to match everything that isn't a space in the string.",
        "You can invert any match by using the uppercase version of the selector <code>\\s</code> versus <code>\\S</code> for example."
      ],
      "tests":[
        "assert(test === 36, 'Your RegEx should have found seven spaces in the <code>testString</code>.');",
        "assert(editor.getValue().match(/\\/\\\\S\\/gi/gi), 'You should be using the following expression <code>/\\S+/gi</code> to find the spaces in the <code>testString</code>.');"
      ],
      "challengeSeed":[
        "var test = (function(){",
        "  var testString = \"How many spaces are there in this sentence.\";",
        "",
        "  // Do not modify the code above this line.",
        "",
        "  var expression = /.+/gi;",
        "",
        "// You can ignore everything below this line.",
        "// We use this function to show you the value of your variable in your output box.",
        " return(testString.match(expression).length);",
        "})();(function(){return(test);})();"
      ],
      "type": "waypoint",
      "challengeType":1
    }
  ]
}