freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/build-javascript-objects.md

id, title, challengeType, videoUrl, forumTopicId, dashedName

id	title	challengeType	videoUrl	forumTopicId	dashedName
56bbb991ad1ed5201cd392d0	Build JavaScript Objects	1	https://scrimba.com/c/cWGkbtd	16769	build-javascript-objects

--description--

You may have heard the term object before.

Objects are similar to arrays, except that instead of using indexes to access and modify their data, you access the data in objects through what are called properties.

Objects are useful for storing data in a structured way, and can represent real world objects, like a cat.

Here's a sample cat object:

var cat = {
  "name": "Whiskers",
  "legs": 4,
  "tails": 1,
  "enemies": ["Water", "Dogs"]
};

In this example, all the properties are stored as strings, such as name, legs, and tails. However, you can also use numbers as properties. You can even omit the quotes for single-word string properties, as follows:

var anotherObject = {
  make: "Ford",
  5: "five",
  "model": "focus"
};

However, if your object has any non-string properties, JavaScript will automatically typecast them as strings.

--instructions--

Make an object that represents a dog called myDog which contains the properties name (a string), legs, tails and friends.

You can set these object properties to whatever values you want, as long as name is a string, legs and tails are numbers, and friends is an array.

--hints--

myDog should contain the property name and it should be a string.

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 legs and it should be a number.

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 tails 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 friends and it should be an array.

assert(
  (function (z) {
    if (
      z.hasOwnProperty('friends') &&
      z.friends !== undefined &&
      Array.isArray(z.friends)
    ) {
      return true;
    } else {
      return false;
    }
  })(myDog)
);

myDog should only contain all the given properties.

assert(
  (function (z) {
    return Object.keys(z).length === 4;
  })(myDog)
);

--seed--

--after-user-code--

(function(z){return z;})(myDog);

--seed-contents--

var myDog = {
// Only change code below this line


// Only change code above this line
};

--solutions--

var myDog = {
  "name": "Camper",
  "legs": 4,
  "tails": 1,
  "friends": ["everything!"]
};