124 lines
3.3 KiB
Markdown
124 lines
3.3 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244bd
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title: Passing Values to Functions with Arguments
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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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---
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## Description
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<section id='description'>
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<dfn>Parameters</dfn> are variables that act as placeholders for the values that are to be input to a function when it is called. When a function is defined, it is typically defined along with one or more parameters. The actual values that are input (or <dfn>"passed"</dfn>) into a function when it is called are known as <dfn>arguments</dfn>.
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Here is a function with two parameters, <code>param1</code> and <code>param2</code>:
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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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Then we can call <code>testFun</code>:
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<code>testFun("Hello", "World");</code>
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We have passed two arguments, <code>"Hello"</code> and <code>"World"</code>. Inside the function, <code>param1</code> will equal "Hello" and <code>param2</code> will equal "World". Note that you could call <code>testFun</code> again with different arguments and the parameters would take on the value of the new arguments.
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</section>
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## Instructions
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<section id='instructions'>
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<ol><li>Create a function called <code>functionWithArgs</code> that accepts two arguments and outputs their sum to the dev console.</li><li>Call the function with two numbers as arguments.</li></ol>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>functionWithArgs</code> should be a function
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testString: assert(typeof functionWithArgs === 'function');
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- text: <code>functionWithArgs(1,2)</code> should output <code>3</code>
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testString: if(typeof functionWithArgs === "function") { capture(); functionWithArgs(1,2); uncapture(); } assert(logOutput == 3);
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- text: <code>functionWithArgs(7,9)</code> should output <code>16</code>
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testString: if(typeof functionWithArgs === "function") { capture(); functionWithArgs(7,9); uncapture(); } assert(logOutput == 16);
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- text: Call <code>functionWithArgs</code> with two numbers after you define it.
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testString: assert(/^\s*functionWithArgs\s*\(\s*\d+\s*,\s*\d+\s*\)\s*/m.test(code));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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// Example
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function ourFunctionWithArgs(a, b) {
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console.log(a - b);
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}
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ourFunctionWithArgs(10, 5); // Outputs 5
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// Only change code below this line.
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```
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</div>
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### Before Test
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<div id='js-setup'>
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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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</div>
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### After Test
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<div id='js-teardown'>
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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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</div>
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</section>
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## Solution
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<section id='solution'>
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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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</section>
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