freeCodeCamp/iterate-over-all-properties.md at 4a74567986d8de748f954e8957adc7613e85193f

Oliver Eyton-Williams 4a74567986 fix: remove title from Chinese chals

2020-10-06 23:10:08 +05:30

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id, challengeType, forumTopicId, localeTitle

id	challengeType	forumTopicId	localeTitle
587d7daf367417b2b2512b7d	1	301320	迭代所有属性

Description

现在你已经了解了两种属性: 自身属性和原型属性。自身属性是直接在对象上定义的。而原型属性是定义在prototype上的：

function Bird(name) {
  this.name = name;  // 自身属性
}

Bird.prototype.numLegs = 2; // 原型属性

let duck = new Bird("Donald");

这个示例会告诉你如何将duck的自身属性和原型属性分别添加到ownProps数组和prototypeProps数组里面：

let ownProps = [];
let prototypeProps = [];

for (let property in duck) {
  if(duck.hasOwnProperty(property)) {
    ownProps.push(property);
  } else {
    prototypeProps.push(property);
  }
}

console.log(ownProps); // prints ["name"]
console.log(prototypeProps); // prints ["numLegs"]

Instructions

将beagle的自身属性都添加到ownProps数组里面去。将Dog的所有原型属性添加到prototypeProps数组中。

Tests

tests:
  - text: "这个<code>ownProps</code>数组应该包含<code>'name'</code>这个值。"
    testString: assert(ownProps.indexOf('name') !== -1);
  - text: "这个<code>prototypeProps</code>数组应该包含<code>'numLegs'</code>这个值。"
    testString: assert(prototypeProps.indexOf('numLegs') !== -1);
  - text: 在不使用内置方法<code>Object.keys()</code>的情况下完成这个挑战。
    testString: assert(!/\Object.keys/.test(code));

Challenge Seed

function Dog(name) {
  this.name = name;
}

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

let ownProps = [];
let prototypeProps = [];

// Add your code below this line

Solution

function Dog(name) {
  this.name = name;
}

Dog.prototype.numLegs = 4;

let beagle = new Dog("Snoopy");

let ownProps = [];
let prototypeProps = [];
for (let prop in beagle) {
  if (beagle.hasOwnProperty(prop)) {
    ownProps.push(prop);
  } else {
    prototypeProps.push(prop);
  }
}

2.4 KiB Raw Blame History