ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
96 lines
2.3 KiB
Markdown
96 lines
2.3 KiB
Markdown
---
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id: cf1111c1c12feddfaeb3bdef
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title: 用 if 语句来表达条件逻辑
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cy87mf3'
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forumTopicId: 18348
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dashedName: use-conditional-logic-with-if-statements
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---
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# --description--
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`If`语句用于在代码中做条件判断。关键字`if`告诉 JavaScript 在小括号中的条件为真的情况下去执行定义在大括号里面的代码。这种条件被称为`Boolean`条件，因为他们只可能是`true`（真）或`false`（假）。
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当条件的计算结果为`true`，程序执行大括号内的语句。当布尔条件的计算结果为`false`，大括号内的代码将不会执行。
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**伪代码**
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<blockquote>if(<i>条件为真</i>){<br> <i>语句被执行</i><br>}</blockquote>
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**示例**
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```js
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function test (myCondition) {
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if (myCondition) {
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return "It was true";
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}
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return "It was false";
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}
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test(true); // returns "It was true"
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test(false); // returns "It was false"
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```
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当`test`被调用，并且传递进来的参数值为`true`，`if`语句会计算`myCondition`的结果，看它是真还是假。如果条件为`true`，函数会返回`"It was true"`。当`test`被调用，并且传递进来的参数值为`false`，`myCondition`*不* 为`true`，并且不执行大括号后面的语句，函数返回`"It was false"`。
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# --instructions--
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在函数内部创建一个`if`语句，如果该参数`wasThatTrue`值为`true`，返回`"Yes, that was true"`，否则，并返回`"No, that was false"`。
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# --hints--
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`trueOrFalse`应该是一个函数。
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```js
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assert(typeof trueOrFalse === 'function');
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```
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`trueOrFalse(true)`应该返回一个字符串。
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```js
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assert(typeof trueOrFalse(true) === 'string');
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```
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`trueOrFalse(false)`应该返回一个字符串。
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```js
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assert(typeof trueOrFalse(false) === 'string');
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```
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`trueOrFalse(true)`应该返回 "Yes, that was true"。
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```js
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assert(trueOrFalse(true) === 'Yes, that was true');
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```
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`trueOrFalse(false)`应该返回 "No, that was false"。
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```js
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assert(trueOrFalse(false) === 'No, that was false');
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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 trueOrFalse(wasThatTrue) {
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// Only change code below this line
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// Only change code above this line
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}
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```
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# --solutions--
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```js
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function trueOrFalse(wasThatTrue) {
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if (wasThatTrue) {
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return "Yes, that was true";
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}
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return "No, that was false";
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}
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```
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