2018-10-10 22:03:03 +00:00
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---
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id: 587d824e367417b2b2512c57
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2021-03-22 13:52:28 +00:00
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title: 测试对象是否是构造函数的实例
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2018-10-10 22:03:03 +00:00
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challengeType: 2
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2020-09-17 10:50:23 +00:00
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forumTopicId: 301605
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2021-01-13 02:31:00 +00:00
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dashedName: test-if-an-object-is-an-instance-of-a-constructor
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2021-05-12 15:55:58 +00:00
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请注意,本项目在[这个 Replit 项目](https://replit.com/github/freeCodeCamp/boilerplate-mochachai)的基础上进行开发。你也可以从 [GitHub](https://repl.it/github/freeCodeCamp/boilerplate-mochachai) 上克隆。
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2020-12-16 07:37:30 +00:00
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2021-03-22 13:52:28 +00:00
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`#instanceOf` 断言一个对象是一个构造器的实例。
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2018-10-10 22:03:03 +00:00
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2021-03-22 13:52:28 +00:00
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在 `tests/1_unit-tests.js` 中,`Objects` 套件里标有 `#18` 的测试下,将每个 `assert` 改成 `assert.instanceOf` 或 `assert.notInstanceOf` 方法,通过测试(结果应该返回 `true`)。 不要修改传给断言的参数。
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2020-12-16 07:37:30 +00:00
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# --hints--
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2021-03-22 13:52:28 +00:00
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应通过所有测试。
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2020-12-16 07:37:30 +00:00
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=17').then(
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(data) => {
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assert.equal(data.state, 'passed');
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-22 13:52:28 +00:00
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应该为第一个断言选择正确的方法:`instanceOf` 或 `notInstanceOf`。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=17').then(
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(data) => {
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assert.equal(
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data.assertions[0].method,
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'notInstanceOf',
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'myCar is not an instance of Plane'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-22 13:52:28 +00:00
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应该为第二个断言选择正确的方法:`instanceOf` 或 `notInstanceOf`。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=17').then(
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(data) => {
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assert.equal(
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data.assertions[1].method,
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'instanceOf',
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'airlinePlane is an instance of Plane'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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2021-03-22 13:52:28 +00:00
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应该为第三个断言选择正确的方法:`instanceOf` 或 `notInstanceOf`。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=17').then(
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(data) => {
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assert.equal(
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data.assertions[2].method,
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'instanceOf',
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'everything is an Object in JavaScript...'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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2018-10-10 22:03:03 +00:00
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```
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2020-08-13 15:24:35 +00:00
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2021-03-22 13:52:28 +00:00
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应该为第四个断言选择正确的方法:`instanceOf` 或 `notInstanceOf`。
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2020-12-16 07:37:30 +00:00
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=17').then(
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(data) => {
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assert.equal(
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data.assertions[3].method,
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'notInstanceOf',
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'myCar.wheels is not an instance of String'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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/**
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Backend challenges don't need solutions,
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because they would need to be tested against a full working project.
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Please check our contributing guidelines to learn more.
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*/
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```
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