2018-10-10 22:03:03 +00:00
|
|
|
---
|
|
|
|
id: 587d824b367417b2b2512c47
|
2021-03-22 13:52:28 +00:00
|
|
|
title: 测试变量或函数是否已定义
|
2018-10-10 22:03:03 +00:00
|
|
|
challengeType: 2
|
2020-09-17 10:50:23 +00:00
|
|
|
forumTopicId: 301602
|
2021-01-13 02:31:00 +00:00
|
|
|
dashedName: test-if-a-variable-or-function-is-defined
|
2018-10-10 22:03:03 +00:00
|
|
|
---
|
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
# --description--
|
|
|
|
|
2021-05-12 15:55:58 +00:00
|
|
|
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。
|
2020-09-17 10:50:23 +00:00
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
# --instructions--
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2021-03-22 13:52:28 +00:00
|
|
|
在 `tests/1_unit-tests.js` 中,`Basic Assertions` 套件中标注为 `#2` 的测试下,修改每个 `assert` 为 `assert.isDefined()` 或 `assert.isUndefined()`,通过测试(结果应为 `true`)。 不要修改传给断言的参数。
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
# --hints--
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2021-03-22 13:52:28 +00:00
|
|
|
应通过所有测试。
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
```js
|
|
|
|
(getUserInput) =>
|
|
|
|
$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
|
|
|
|
(data) => {
|
|
|
|
assert.equal(data.state, 'passed');
|
|
|
|
},
|
|
|
|
(xhr) => {
|
|
|
|
throw new Error(xhr.responseText);
|
|
|
|
}
|
|
|
|
);
|
2018-10-10 22:03:03 +00:00
|
|
|
```
|
|
|
|
|
2021-03-22 13:52:28 +00:00
|
|
|
应该为第一个断言选择正确的方法:`isDefined` 或 `isUndefined`。
|
2020-12-16 07:37:30 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
(getUserInput) =>
|
|
|
|
$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
|
|
|
|
(data) => {
|
|
|
|
assert.equal(
|
|
|
|
data.assertions[0].method,
|
|
|
|
'isDefined',
|
|
|
|
'Null is not undefined'
|
|
|
|
);
|
|
|
|
},
|
|
|
|
(xhr) => {
|
|
|
|
throw new Error(xhr.responseText);
|
|
|
|
}
|
|
|
|
);
|
|
|
|
```
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2021-03-22 13:52:28 +00:00
|
|
|
应该为第二个断言选择正确的方法:`isDefined` 或 `isUndefined`。
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
```js
|
|
|
|
(getUserInput) =>
|
|
|
|
$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
|
|
|
|
(data) => {
|
|
|
|
assert.equal(
|
|
|
|
data.assertions[1].method,
|
|
|
|
'isUndefined',
|
|
|
|
'Undefined is undefined'
|
|
|
|
);
|
|
|
|
},
|
|
|
|
(xhr) => {
|
|
|
|
throw new Error(xhr.responseText);
|
|
|
|
}
|
|
|
|
);
|
|
|
|
```
|
2018-10-10 22:03:03 +00:00
|
|
|
|
2021-03-22 13:52:28 +00:00
|
|
|
应该为第三个断言选择正确的方法:`isDefined` 或 `isUndefined`。
|
2018-10-10 22:03:03 +00:00
|
|
|
|
|
|
|
```js
|
2020-12-16 07:37:30 +00:00
|
|
|
(getUserInput) =>
|
|
|
|
$.get(getUserInput('url') + '/_api/get-tests?type=unit&n=1').then(
|
|
|
|
(data) => {
|
|
|
|
assert.equal(
|
|
|
|
data.assertions[2].method,
|
|
|
|
'isDefined',
|
|
|
|
'A string is not undefined'
|
|
|
|
);
|
|
|
|
},
|
|
|
|
(xhr) => {
|
|
|
|
throw new Error(xhr.responseText);
|
|
|
|
}
|
|
|
|
);
|
2018-10-10 22:03:03 +00:00
|
|
|
```
|
2020-08-13 15:24:35 +00:00
|
|
|
|
2020-12-16 07:37:30 +00:00
|
|
|
# --solutions--
|
|
|
|
|
2021-01-13 02:31:00 +00:00
|
|
|
```js
|
|
|
|
/**
|
|
|
|
Backend challenges don't need solutions,
|
|
|
|
because they would need to be tested against a full working project.
|
|
|
|
Please check our contributing guidelines to learn more.
|
|
|
|
*/
|
|
|
|
```
|