badeb6e2df
Suggesting the removal of "-" on line 29 in the description, as the comma before "such" is sufficient to separate the examples from the rest of the sentence.
160 lines
3.0 KiB
Markdown
160 lines
3.0 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392d0
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title: Build JavaScript Objects
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cWGkbtd'
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forumTopicId: 16769
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dashedName: build-javascript-objects
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---
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# --description--
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You may have heard the term `object` before.
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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`.
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Objects are useful for storing data in a structured way, and can represent real world objects, like a cat.
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Here's a sample cat object:
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```js
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var cat = {
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"name": "Whiskers",
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"legs": 4,
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"tails": 1,
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"enemies": ["Water", "Dogs"]
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};
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```
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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:
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```js
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var anotherObject = {
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make: "Ford",
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5: "five",
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"model": "focus"
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};
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```
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However, if your object has any non-string properties, JavaScript will automatically typecast them as strings.
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# --instructions--
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Make an object that represents a dog called `myDog` which contains the properties `name` (a string), `legs`, `tails` and `friends`.
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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.
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# --hints--
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`myDog` should contain the property `name` and it should be a `string`.
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```js
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assert(
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(function (z) {
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if (
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z.hasOwnProperty('name') &&
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z.name !== undefined &&
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typeof z.name === 'string'
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) {
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return true;
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} else {
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return false;
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}
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})(myDog)
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);
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```
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`myDog` should contain the property `legs` and it should be a `number`.
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```js
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assert(
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(function (z) {
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if (
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z.hasOwnProperty('legs') &&
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z.legs !== undefined &&
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typeof z.legs === 'number'
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) {
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return true;
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} else {
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return false;
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}
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})(myDog)
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);
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```
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`myDog` should contain the property `tails` and it should be a `number`.
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```js
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assert(
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(function (z) {
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if (
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z.hasOwnProperty('tails') &&
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z.tails !== undefined &&
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typeof z.tails === 'number'
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) {
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return true;
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} else {
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return false;
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}
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})(myDog)
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);
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```
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`myDog` should contain the property `friends` and it should be an `array`.
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```js
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assert(
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(function (z) {
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if (
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z.hasOwnProperty('friends') &&
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z.friends !== undefined &&
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Array.isArray(z.friends)
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) {
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return true;
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} else {
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return false;
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}
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})(myDog)
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);
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```
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`myDog` should only contain all the given properties.
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```js
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assert(
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(function (z) {
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return Object.keys(z).length === 4;
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})(myDog)
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);
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```
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# --seed--
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## --after-user-code--
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```js
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(function(z){return z;})(myDog);
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```
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## --seed-contents--
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```js
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var myDog = {
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// Only change code below this line
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// Only change code above this line
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};
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```
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# --solutions--
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```js
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var myDog = {
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"name": "Camper",
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"legs": 4,
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"tails": 1,
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"friends": ["everything!"]
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};
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```
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