2018-10-10 22:03:03 +00:00
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---
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id: 56533eb9ac21ba0edf2244d1
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2021-03-15 03:20:39 +00:00
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title: 严格相等运算符
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-04-29 10:29:13 +00:00
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videoUrl: 'https://scrimba.com/c/cy87atr'
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forumTopicId: 16790
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2021-01-13 02:31:00 +00:00
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dashedName: comparison-with-the-strict-equality-operator
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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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2021-03-15 03:20:39 +00:00
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严格相等运算符(`===`)是相对相等操作符(`==`)的另一种比较操作符。 与相等操作符转换数据两类型不同,严格相等运算符不会做类型转换。
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2020-12-16 07:37:30 +00:00
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2021-03-15 03:20:39 +00:00
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如果比较的值类型不同,那么在严格相等运算符比较下它们是不相等的,会返回 false 。
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2020-12-16 07:37:30 +00:00
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2021-03-15 03:20:39 +00:00
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**示例**
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2020-04-29 10:29:13 +00:00
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```js
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2021-03-15 03:20:39 +00:00
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3 === 3
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3 === '3'
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2020-04-29 10:29:13 +00:00
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```
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2021-03-15 03:20:39 +00:00
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这些条件将分别返回 `true` and `false`。
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在第二个例子中,`3` 是一个 `Number` 类型,而 `'3'` 是一个 `String` 类型。
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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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# --instructions--
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2018-10-10 22:03:03 +00:00
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2021-11-06 15:56:52 +00:00
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在 `if` 语句中使用严格相等运算符,这样当 `val` 严格等于 `7` 时,函数将返回字符串 `Equal`。
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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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# --hints--
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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`testStrict(10)` 应该返回字符串 `Not Equal`
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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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assert(testStrict(10) === 'Not Equal');
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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`testStrict(7)` 应该返回字符串 `Equal`
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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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assert(testStrict(7) === 'Equal');
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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`testStrict("7")` 应该返回字符串 `Not Equal`
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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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assert(testStrict('7') === 'Not Equal');
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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你应该使用 `===` 运算符。
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2020-04-29 10:29:13 +00:00
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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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assert(code.match(/(val\s*===\s*\d+)|(\d+\s*===\s*val)/g).length > 0);
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2018-10-10 22:03:03 +00:00
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```
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2020-04-29 10:29:13 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --seed-contents--
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```js
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// Setup
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function testStrict(val) {
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if (val) { // Change this line
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return "Equal";
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}
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return "Not Equal";
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}
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testStrict(10);
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```
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2020-12-16 07:37:30 +00:00
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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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function testStrict(val) {
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if (val === 7) {
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return "Equal";
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}
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return "Not Equal";
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}
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```
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