71 lines
1.4 KiB
Markdown
71 lines
1.4 KiB
Markdown
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---
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id: 587d7dad367417b2b2512b75
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title: 在對象上創建方法
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challengeType: 1
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forumTopicId: 301318
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dashedName: create-a-method-on-an-object
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---
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# --description--
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對象可以有一個叫做 <dfn>method</dfn> 的特殊屬性。
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方法屬性也就是函數。 這給對象添加了不同的行爲。 以下就是一個帶有方法屬性的 `duck` 示例：
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```js
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let duck = {
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name: "Aflac",
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numLegs: 2,
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sayName: function() {return "The name of this duck is " + duck.name + ".";}
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};
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duck.sayName();
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```
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示例添加了 `sayName` 方法，函數返回包含 `duck` 名字的一個句子。 注意：這個方法在返回語句中使用 `duck.name` 的方式來獲取 `name` 的屬性值。 在下一個挑戰中我們將會使用另外一種方法來實現。
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# --instructions--
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給 `dog` 對象設置一個名爲 `sayLegs` 的方法。 並讓它返回 `This dog has 4 legs.` 這句話。
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# --hints--
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`dog.sayLegs()` 應該是一個函數。
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```js
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assert(typeof dog.sayLegs === 'function');
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```
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`dog.sayLegs()` 應該返回給定的字符串，需要注意標點和間距的問題。
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```js
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assert(dog.sayLegs() === 'This dog has 4 legs.');
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```
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# --seed--
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## --seed-contents--
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```js
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let dog = {
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name: "Spot",
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numLegs: 4,
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};
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dog.sayLegs();
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```
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# --solutions--
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```js
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let dog = {
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name: "Spot",
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numLegs: 4,
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sayLegs () {
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return 'This dog has ' + this.numLegs + ' legs.';
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}
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};
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dog.sayLegs();
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```
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