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>
102 lines
2.2 KiB
Markdown
102 lines
2.2 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392cf
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title: 用函数编写可重用代码
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cL6dqfy'
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forumTopicId: 18378
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dashedName: write-reusable-javascript-with-functions
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---
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# --description--
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在 JavaScript 中，我们可以把代码的重复部分抽取出来，放到一个<dfn>函数</dfn>中。
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举个例子：
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```js
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function functionName() {
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console.log("Hello World");
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}
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```
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你可以通过函数名`functionName`加上后面的小括号来调用这个函数，就像这样： `functionName();` 每次调用函数时，它都会在控制台上打印消息`"Hello World"`。每次调用函数时，大括号之间的所有代码都将被执行。
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# --instructions--
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<ol><li>先创建一个名为<code>reusableFunction</code>的函数，这个函数可以打印<code>"Hi World"</code>到控制台上。</li><li>然后调用这个函数。</li></ol>
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# --hints--
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`reusableFunction`应该是一个函数。
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```js
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assert(typeof reusableFunction === 'function');
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```
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`reusableFunction`应该在控制台中输出 "Hi World"。
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```js
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assert(hiWorldWasLogged);
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```
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在你定义`reusableFunction`之后记得调用它。
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```js
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assert(/^\s*reusableFunction\(\)\s*/m.test(code));
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```
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# --seed--
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## --before-user-code--
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```js
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var logOutput = "";
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var originalConsole = console;
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var nativeLog = console.log;
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var hiWorldWasLogged = false;
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function capture() {
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console.log = function (message) {
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if(message === 'Hi World') hiWorldWasLogged = true;
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if(message && message.trim) logOutput = message.trim();
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if(nativeLog.apply) {
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nativeLog.apply(originalConsole, arguments);
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} else {
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var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
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nativeLog(nativeMsg);
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}
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};
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}
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function uncapture() {
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console.log = nativeLog;
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}
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capture();
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```
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## --after-user-code--
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```js
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uncapture();
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if (typeof reusableFunction !== "function") {
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(function() { return "reusableFunction is not defined"; })();
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} else {
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(function() { return logOutput || "console.log never called"; })();
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}
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```
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## --seed-contents--
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```js
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```
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# --solutions--
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```js
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function reusableFunction() {
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console.log("Hi World");
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}
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reusableFunction();
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```
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