121 lines
2.8 KiB
Markdown
121 lines
2.8 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244bd
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title: 將值傳遞給帶有參數的函數
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cy8rahW'
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forumTopicId: 18254
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dashedName: passing-values-to-functions-with-arguments
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---
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# --description--
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函數的參數 (<dfn>parameters</dfn>)在函數調用中充當傳入函數的輸入佔位符(也叫形參)。 函數調用時,參數可以爲一個或多個。 調用函數時輸入(或傳遞 <dfn>"passed"</dfn>)的實際值被稱爲參數(<dfn>arguments</dfn>)。
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這是帶有兩個參數的函數,`param1` 和 `param2`:
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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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然後我們可以調用 `testFun`,就像這樣: `testFun("Hello", "World");`。 我們傳入了兩個字符串參數, `Hello` 和 `World`。 在函數中,`param1` 等於字符串 `Hello` 以及 `param2` 等於字符串 `World`。 請注意,`testFun` 函數可以多次調用,每次調用時傳遞的參數會決定參數的實際值。
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# --instructions--
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<ol><li>創建一個名爲 <code>functionWithArgs</code> 的函數,它可以接收兩個參數,計算參數的和,將結果輸出到控制檯。</li><li>用兩個數字作爲參數調用函數。</li></ol>
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# --hints--
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`functionWithArgs` 應該是一個函數。
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```js
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assert(typeof functionWithArgs === 'function');
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```
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`functionWithArgs(1,2)` 應該輸出 `3`。
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```js
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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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}
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assert(logOutput == 3);
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```
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`functionWithArgs(7,9)` 應該輸出 `16`。
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```js
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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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}
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assert(logOutput == 16);
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```
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在定義 `functionWithArgs` 之後記得傳入兩個數字調用它。
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```js
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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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```
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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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```js
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```
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# --solutions--
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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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