107 lines
2.0 KiB
Markdown
107 lines
2.0 KiB
Markdown
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---
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id: 587d7daf367417b2b2512b7d
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title: 迭代所有屬性
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challengeType: 1
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forumTopicId: 301320
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dashedName: iterate-over-all-properties
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---
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# --description--
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現在你已經瞭解了兩種屬性: <dfn>自身屬性</dfn>和 `prototype` 屬性。 自身屬性是直接在對象上定義的。 而 `prototype` 屬性是定義在 `prototype` 上的。
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```js
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function Bird(name) {
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this.name = name; //own property
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}
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Bird.prototype.numLegs = 2; // prototype property
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let duck = new Bird("Donald");
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```
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這個示例會告訴你如何將 `duck` 的自身屬性和 `prototype` 屬性分別添加到 `ownProps` 數組和 `prototypeProps` 數組裏面:
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```js
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let ownProps = [];
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let prototypeProps = [];
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for (let property in duck) {
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if(duck.hasOwnProperty(property)) {
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ownProps.push(property);
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} else {
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prototypeProps.push(property);
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}
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}
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console.log(ownProps);
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console.log(prototypeProps);
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```
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`console.log(ownProps)` 將在控制檯中顯示 `["name"]` ,`console.log(prototypeProps)` 將顯示 `["numLegs"]`。
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# --instructions--
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將 `beagle` 的自身屬性都添加到 `ownProps` 數組裏面去。 將 `Dog` 中所有的 `prototype` 屬性都添加到 `prototypeProps` 數組中。
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# --hints--
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`ownProps` 數組應該包含 `name`。
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```js
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assert.deepEqual(ownProps, ['name']);
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```
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`prototypeProps` 數組應該包含 `numLegs`。
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```js
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assert.deepEqual(prototypeProps, ['numLegs']);
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```
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在不使用內置方法 `Object.keys()` 的前提下完成這個挑戰。
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```js
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assert(!/\Object.keys/.test(code));
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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(name) {
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this.name = name;
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}
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Dog.prototype.numLegs = 4;
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let beagle = new Dog("Snoopy");
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let ownProps = [];
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let prototypeProps = [];
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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(name) {
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this.name = name;
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}
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Dog.prototype.numLegs = 4;
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let beagle = new Dog("Snoopy");
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let ownProps = [];
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let prototypeProps = [];
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for (let prop in beagle) {
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if (beagle.hasOwnProperty(prop)) {
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ownProps.push(prop);
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} else {
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prototypeProps.push(prop);
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}
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}
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```
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