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>
71 lines
1.3 KiB
Markdown
71 lines
1.3 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244ba
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title: 了解字符串的不变性
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cWPVaUR'
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forumTopicId: 18331
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dashedName: understand-string-immutability
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---
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# --description--
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在 JavaScript 中，`字符串`的值是 <dfn>不可变的</dfn>，这意味着一旦字符串被创建就不能被改变。
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例如，下面的代码：
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```js
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var myStr = "Bob";
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myStr[0] = "J";
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```
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是不会把变量`myStr`的值改变成 "Job" 的，因为变量`myStr`是不可变的。注意，这*并不*意味着`myStr`永远不能被改变，只是字符串字面量 <dfn>string literal</dfn> 的各个字符不能被改变。改变`myStr`中的唯一方法是重新给它赋一个值，例如：
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```js
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var myStr = "Bob";
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myStr = "Job";
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```
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# --instructions--
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把`myStr`的值改为`Hello World`。
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# --hints--
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message:`myStr`的值应该是`Hello World`。
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```js
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assert(myStr === 'Hello World');
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```
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不要修改注释上面的代码。
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```js
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assert(/myStr = "Jello World"/.test(code));
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```
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# --seed--
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## --after-user-code--
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```js
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(function(v){return "myStr = " + v;})(myStr);
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```
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## --seed-contents--
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```js
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// Setup
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var myStr = "Jello World";
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// Only change code below this line
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myStr[0] = "H"; // Change this line
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// Only change code above this line
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```
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# --solutions--
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```js
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var myStr = "Jello World";
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myStr = "Hello World";
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```
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