80 lines
1.7 KiB
Markdown
80 lines
1.7 KiB
Markdown
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---
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id: 587d7dad367417b2b2512b78
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title: Use a Constructor to Create Objects
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challengeType: 1
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forumTopicId: 18233
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dashedName: use-a-constructor-to-create-objects
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---
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# --description--
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Here's the `Bird` constructor from the previous challenge:
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```js
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function Bird() {
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this.name = "Albert";
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this.color = "blue";
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this.numLegs = 2;
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// "this" inside the constructor always refers to the object being created
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}
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let blueBird = new Bird();
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```
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Notice that the `new` operator is used when calling a constructor. This tells JavaScript to create a new instance of `Bird` called `blueBird`. Without the `new` operator, `this` inside the constructor would not point to the newly created object, giving unexpected results. Now `blueBird` has all the properties defined inside the `Bird` constructor:
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```js
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blueBird.name; // => Albert
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blueBird.color; // => blue
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blueBird.numLegs; // => 2
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```
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Just like any other object, its properties can be accessed and modified:
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```js
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blueBird.name = 'Elvira';
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blueBird.name; // => Elvira
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```
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# --instructions--
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Use the `Dog` constructor from the last lesson to create a new instance of `Dog`, assigning it to a variable `hound`.
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# --hints--
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`hound` should be created using the `Dog` constructor.
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```js
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assert(hound instanceof Dog);
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```
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Your code should use the `new` operator to create an instance of `Dog`.
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```js
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assert(code.match(/new/g));
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```
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# --seed--
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## --seed-contents--
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```js
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function Dog() {
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this.name = "Rupert";
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this.color = "brown";
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this.numLegs = 4;
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}
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// Only change code below this line
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```
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# --solutions--
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```js
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function Dog() {
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this.name = "Rupert";
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this.color = "brown";
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this.numLegs = 4;
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}
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const hound = new Dog();
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```
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