diff --git a/seed/challenges/object-oriented-and-functional-programming.json b/seed/challenges/object-oriented-and-functional-programming.json index d80a50de85..10defbc1bb 100644 --- a/seed/challenges/object-oriented-and-functional-programming.json +++ b/seed/challenges/object-oriented-and-functional-programming.json @@ -178,17 +178,19 @@ "title":"Iterate over Arrays with .map", "difficulty":0, "description":[ - "The map method is one of the easiest ways to iterate through an array or object there is. Let's use it now.", - "array = array.map(function(val){", - "  return val+1;", + "The map method is a convenient way to iterate through arrays. Here's an example usage:", + "var timesFour = array.map(function(val){", + "  return val*4;", "});", "", + "The map method will iterate through every element of the array, creating a new array with values that have been modified by the callback function, and return it.", + "In our example the callback only uses the value of the array element (the val argument) but your callback can also include arguments for the index and array being acted on.", "Use the map function to add 3 to every value in the variable array." ], "tests":[ "assert.deepEqual(array, [4,5,6,7,8], 'message: You should add three to each value in the array.');", - "assert(editor.getValue().match(/\\.map\\s*\\(/gi), 'message: You should be making use of the map method.');", - "assert(editor.getValue().match(/\\[1\\,2\\,3\\,4\\,5\\]/gi), 'message: You should only modify the array with .map.');" + "assert(editor.getValue().match(/\\.map\\s*\\(/gi), 'message: You should be making use of the map method.');", + "assert(editor.getValue().match(/\\[1\\,2\\,3\\,4\\,5\\]/gi), 'message: You should only modify the array with map.');" ], "challengeSeed":[ "//Use map to add three to each value in the array", @@ -211,15 +213,18 @@ "title":"Condense arrays with .reduce", "difficulty":0, "description":[ - "Reduce can be useful for condensing an array of numbers into one value.", + "The array method reduce is used to iterate through an array and condense it into one value.", + "To use reduce you pass in a callback whose arguments are an accumulator (in this case, previousVal) and the current value (currentVal).", + "reduce has an optional second argument which can be used to set the initial value of the accumulator. If no initial value is specified if will be the first array element.", + "Here is an example of reduce being used to sum all the values of an array:", "var singleVal = array.reduce(function(previousVal, currentVal){", "  return previousVal+currentVal;", "});", - "Use the reduce function to sum all the values in array and assign it to singleVal." + "Use the reduce method to sum all the values in array and assign it to singleVal." ], "tests":[ "assert(singleVal == 30, 'message: singleVal should be equal to the sum of all items in the array variable.');", - "assert(editor.getValue().match(/\\.reduce\\s*\\(/gi), 'message: You should have made use of the reduce method.');" + "assert(editor.getValue().match(/\\.reduce\\s*\\(/gi), 'message: You should have made use of the reduce method.');" ], "challengeSeed":[ "var array = [4,5,6,7,8];", @@ -242,24 +247,27 @@ "title":"Filter Arrays with .filter", "difficulty":0, "description":[ - "Filter is a useful method that can filter out values that don't match a certain criteria", - "Let's remove all the values greater than five", + "The filter method is used to iterate through an array and filter out elements where a given condition is not true.", + "filter is passed a callback function which takes the current value (we've called that val) as an argument. It can also use arguments for the index and array being acted on.", + "Any array element for which the callback returns true will be kept and elements that return false will be filtered out.", + "The following code is an example of using filter to remove array elements that are not even numbers:", "array = array.filter(function(val) {", - "  return val <= 5;", - "});" + "  return val % 2 === 0;", + "});", + "Use filter to remove all elements from array that are greater than 5." ], "tests":[ "assert.deepEqual(array, [1,2,3,4,5], 'message: You should have removed all the values from the array that are greater than 5.');", - "assert(editor.getValue().match(/array\\.filter\\s*\\(/gi), 'message: You should be using the filter method to remove the values from the array.');", - "assert(editor.getValue().match(/\\[1\\,2\\,3\\,4\\,5\\,6\\,7\\,8\\,9\\,10\\]/gi), 'message: You should only be using .filter to modify the contents of the array.');" + "assert(editor.getValue().match(/array\\.filter\\s*\\(/gi), 'message: You should be using the filter method to remove the values from the array.');", + "assert(editor.getValue().match(/\\[1\\,2\\,3\\,4\\,5\\,6\\,7\\,8\\,9\\,10\\]/gi), 'message: You should only be using filter to modify the contents of the array.');" ], "challengeSeed":[ "var array = [1,2,3,4,5,6,7,8,9,10];", - " // Only change code below this line.", + "// Only change code below this line.", "", "", "", - " // Only change code above this line.", + "// Only change code above this line.", "(function() {return array;})();" ], "MDNlinks":[ @@ -273,16 +281,20 @@ "title": "Sort Arrays with .sort", "difficulty":0, "description":[ - "You can use the method sort to easily sort the values in the array alphabetically or numerically.", - "var array = [1, 3, 2];", - "array = array.sort();", - "array is now [1, 2, 3].", + "You can use the method sort to easily sort the values in an array alphabetically or numerically.", + "Unlike the previous array methods we have been looking at, sort actually alters the array in place. However, it also returns this sorted array.", + "sort can be passed a compare function as a callback. If no compare function is passed in it will convert the values to strings and sort alphabetically.", + "Here is an example of using sort with a compare function that will sort the elements from smallest to largest number:", + "var array = [1, 12, 21, 2];", + "array.sort(function(a, b) {", + "  return a - b;", + "});", "Use sort to sort array alphabetically." ], "tests":[ "assert.deepEqual(array, ['alpha', 'beta', 'charlie'], 'message: You should have sorted the array alphabetically.');", - "assert(editor.getValue().match(/\\[\\'beta\\'\\,\\s\\'alpha\\'\\,\\s'charlie\\'\\];/gi), 'message: You should only be using .sort to modify the array.');", - "assert(editor.getValue().match(/\\.sort\\s*\\(\\)/gi), 'message: You should have made use of the sort method.');" + "assert(editor.getValue().match(/\\[\\'beta\\'\\,\\s\\'alpha\\'\\,\\s'charlie\\'\\];/gi), 'message: You should only be using sort to modify the array.');", + "assert(editor.getValue().match(/\\.sort\\s*\\(\\)/gi), 'message: You should have made use of the sort method.');" ], "challengeSeed":[ "var array = ['beta', 'alpha', 'charlie'];", @@ -290,7 +302,7 @@ "", "", "", - " // Only change code above this line.", + "// Only change code above this line.", "(function() {return array;})();" ], "MDNlinks":[ @@ -303,7 +315,8 @@ "id": "cf1111c1c16feddfaeb2bdef", "title": "Reverse Arrays with .reverse", "description": [ - "You can use the reverse function to reverse the contents of an array.", + "You can use the reverse method to reverse the elements of an array.", + "reverse is another array method that alters the array in place, but it also returns the reversed array.", "Add a line of code that uses reverse to reverse the array variable." ], "tests": [ @@ -313,11 +326,11 @@ ], "challengeSeed": [ "var array = [1,2,3,4,5,6,7];", - " // Only change code below this line.", + "// Only change code below this line.", "", "", "", - " // Only change code above this line.", + "// Only change code above this line.", "(function() {return array;})();" ], "MDNlinks":[ @@ -330,12 +343,14 @@ "id": "cf1111c1c16feddfaeb3bdef", "title": "Concatenate Strings with .concat", "description": [ - ".concat() can be used to merge the contents of two arrays into one.", + "concat can be used to merge the contents of two arrays into one.", + "concat takes an array as an argument and returns a new array with the elements of this array concatenated onto the end.", + "Here is an example of concat being used to concatenate otherArray onto the end of array:", "array = array.concat(otherArray);", - "Use .concat() to concatenate concatMe onto the end of array and assign it back to array." + "Use .concat() to concatenate concatMe onto the end of array and assign it back to array." ], "tests": [ - "assert.deepEqual(array, [1,2,3,4,5,6], 'message: You should concat the two arrays together.');", + "assert.deepEqual(array, [1,2,3,4,5,6], 'message: You should concatenate the two arrays together.');", "assert(editor.getValue().match(/\\.concat\\s*\\(/gi), 'message: You should be using the concat method to merge the two arrays.');", "assert(editor.getValue().match(/\\[1\\,2\\,3\\]/gi) && editor.getValue().match(/\\[4\\,5\\,6\\]/gi), 'message: You should only be using concat to modify the arrays.');" ], @@ -361,14 +376,15 @@ "title":"Split Strings with .split", "difficulty":0, "description":[ - "You can use the .split() method to split a string into an array.", - ".split() uses the argument you pass in as a delimiter to determine which points the string should be split at.", + "You can use the split method to split a string into an array.", + "split uses the argument you pass in as a delimiter to determine which points the string should be split at.", + "Here is an example of split being used to split an array at every space character:", "var array = string.split(' ');", - "Use .split() to create an array of words from string and assign it to array." + "Use split to create an array of words from string and assign it to array." ], "tests":[ "assert(typeof(array) === 'object' && array.length === 5, 'message: You should split the string by its spaces.');", - "assert(/\\.split\\(/gi, 'message: You should use the split method on the string.');" + "assert(/\\.split\\(/gi, 'message: You should use the split method on the string.');" ], "challengeSeed":[ "var string = \"Split me into an array\";", @@ -390,25 +406,26 @@ "title":"Join Strings with .join", "difficulty":0, "description":[ - "We can use the .join() method to join each element in an array into a string separated by whatever delimiter you provide as an argument to the join operation.", - "var joinMe = joinMe.join(\" \");", - "Use the .join() method to create a string from joinMe with spaces in between each element and assign it back to joinMe." + "We can use the join method to join each element of an array into a string separated by whatever delimiter you provide as an argument.", + "The following is an example of using join to join all of the elements of an array into a string with all the elements seperated by a space:", + "var joinedString = joinMe.join(\" \");", + "Use the join method to create a string from joinMe with spaces in between each element and assign it to joinedString." ], "tests":[ - "assert(typeof(joinMe) === 'string' && joinMe === \"Split me into an array\", 'message: You should join the elements of the array with spaces.');", - "assert(/\\.join\\(/gi, 'message: You should use of the join method on the array.');" + "assert(typeof(joinedString) === 'string' && joinedString === \"Split me into an array\", 'message: You should join the elements of the array with spaces.');", + "assert(/\\.join\\(/gi, 'message: You should use of the join method on the array.');" ], "challengeSeed":[ "var joinMe = [\"Split\",\"me\",\"into\",\"an\",\"array\"];", "// Only change code below this line.", "", - "joinMe = joinMe;", + "var joinedString = joinMe;", "", "// Only change code above this line.", - "(function() {return joinMe;})();" + "(function() {return joinedString;})();" ], "MDNlinks":[ - "Array.join()" + "Array.join()" ], "challengeType":1, "type": "waypoint"