2018-10-10 18:03:03 -04:00
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---
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id: 56533eb9ac21ba0edf2244bd
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2021-03-14 21:20:39 -06:00
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title: 将值传递给带有参数的函数
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2018-10-10 18:03:03 -04:00
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challengeType: 1
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2020-04-29 18:29:13 +08:00
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videoUrl: 'https://scrimba.com/c/cy8rahW'
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forumTopicId: 18254
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2021-01-13 03:31:00 +01:00
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dashedName: passing-values-to-functions-with-arguments
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2018-10-10 18:03:03 -04:00
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---
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2020-12-16 00:37:30 -07:00
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# --description--
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2021-05-10 01:12:02 +05:30
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函数的参数 (<dfn>parameters</dfn>)在函数调用中充当传入函数的输入占位符(也叫形参)。 函数调用时,参数可以为一个或多个。 调用函数时输入(或传递 <dfn>"passed"</dfn>)的实际值被称为参数(<dfn>arguments</dfn>)。
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2020-12-16 00:37:30 -07:00
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2021-03-14 21:20:39 -06:00
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这是带有两个参数的函数,`param1` 和 `param2`:
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2020-04-29 18:29:13 +08:00
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```js
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function testFun(param1, param2) {
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console.log(param1, param2);
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}
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```
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2021-06-02 19:46:30 +09:00
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然后我们可以调用 `testFun`,就像这样: `testFun("Hello", "World");`。 我们传入了两个字符串参数, `Hello` 和 `World`。 在函数中,`param1` 等于字符串 `Hello` 以及 `param2` 等于字符串 `World`。 请注意,`testFun` 函数可以多次调用,每次调用时传递的参数会决定参数的实际值。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --instructions--
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2018-10-10 18:03:03 -04:00
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2021-03-14 21:20:39 -06:00
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<ol><li>创建一个名为 <code>functionWithArgs</code> 的函数,它可以接收两个参数,计算参数的和,将结果输出到控制台。</li><li>用两个数字作为参数调用函数。</li></ol>
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --hints--
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2018-10-10 18:03:03 -04:00
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2021-03-14 21:20:39 -06:00
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`functionWithArgs` 应该是一个函数。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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assert(typeof functionWithArgs === 'function');
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2018-10-10 18:03:03 -04:00
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```
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2021-03-14 21:20:39 -06:00
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`functionWithArgs(1,2)` 应该输出 `3`。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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if (typeof functionWithArgs === 'function') {
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capture();
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functionWithArgs(1, 2);
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uncapture();
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2018-10-10 18:03:03 -04:00
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}
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2020-12-16 00:37:30 -07:00
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assert(logOutput == 3);
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2018-10-10 18:03:03 -04:00
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```
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2021-03-14 21:20:39 -06:00
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`functionWithArgs(7,9)` 应该输出 `16`。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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if (typeof functionWithArgs === 'function') {
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capture();
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functionWithArgs(7, 9);
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uncapture();
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2020-04-29 18:29:13 +08:00
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}
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2020-12-16 00:37:30 -07:00
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assert(logOutput == 16);
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2018-10-10 18:03:03 -04:00
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```
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2021-03-14 21:20:39 -06:00
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在定义 `functionWithArgs` 之后记得传入两个数字调用它。
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2020-04-29 18:29:13 +08:00
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2018-10-10 18:03:03 -04:00
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```js
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2021-02-06 04:42:36 +00:00
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assert(
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/functionWithArgs\([-+]?\d*\.?\d*,[-+]?\d*\.?\d*\)/.test(
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code.replace(/\s/g, '')
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)
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);
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2018-10-10 18:03:03 -04:00
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```
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2020-04-29 18:29:13 +08:00
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2021-01-13 03:31:00 +01:00
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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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function capture() {
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var nativeLog = console.log;
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console.log = function (message) {
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if(message) logOutput = JSON.stringify(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 = originalConsole.log;
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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 functionWithArgs !== "function") {
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(function() { return "functionWithArgs 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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2021-03-14 21:20:39 -06:00
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2021-01-13 03:31:00 +01:00
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```js
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2021-03-14 21:20:39 -06:00
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2021-01-13 03:31:00 +01:00
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```
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2020-12-16 00:37:30 -07:00
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# --solutions--
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2021-01-13 03:31:00 +01:00
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```js
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function functionWithArgs(a, b) {
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console.log(a + b);
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}
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functionWithArgs(10, 5);
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```
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