freeCodeCamp/passing-values-to-functions-with-arguments.md at 4a74567986d8de748f954e8957adc7613e85193f

Oliver Eyton-Williams 4a74567986 fix: remove title from Chinese chals

2020-10-06 23:10:08 +05:30

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id, challengeType, videoUrl, forumTopicId, localeTitle

id	challengeType	videoUrl	forumTopicId	localeTitle
56533eb9ac21ba0edf2244bd	1	https://scrimba.com/c/cy8rahW	18254	将值传递给带有参数的函数

Description

函数的参数parameters在函数中充当占位符(也叫形参)的作用，参数可以为一个或多个。调用一个函数时所传入的参数为实参，实参决定着形参真正的值。简单理解：形参即形式、实参即内容。这是带有两个参数的函数，param1和param2：

function testFun(param1, param2) {
  console.log(param1, param2);
}

接着我们调用testFun： testFun("Hello", "World"); 我们传递了两个参数，"Hello"和"World"。在函数内部，param1等于“Hello”，param2等于“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形参的实际值。

Instructions

创建一个名为functionWithArgs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。
调用这个函数。

Tests

tests:
  - text: <code>functionWithArgs</code>应该是一个函数。
    testString: assert(typeof functionWithArgs === 'function');
  - text: <code>functionWithArgs(1,2)</code>应该输出<code>3</code>。
    testString: if(typeof functionWithArgs === "function") { capture(); functionWithArgs(1,2); uncapture(); } assert(logOutput == 3);
  - text: <code>functionWithArgs(7,9)</code>应该输出<code>16</code>。
    testString: if(typeof functionWithArgs === "function") { capture(); functionWithArgs(7,9); uncapture(); } assert(logOutput == 16);
  - text: 在你定义<code>functionWithArgs</code>之后记得调用它。
    testString: assert(/^\s*functionWithArgs\s*\(\s*\d+\s*,\s*\d+\s*\)\s*;?/m.test(code));

Challenge Seed

// Example
function ourFunctionWithArgs(a, b) {
  console.log(a - b);
}
ourFunctionWithArgs(10, 5); // Outputs 5

// Only change code below this line.

Before Test

var logOutput = "";
var originalConsole = console
function capture() {
    var nativeLog = console.log;
    console.log = function (message) {
        if(message) logOutput = JSON.stringify(message).trim();
        if(nativeLog.apply) {
          nativeLog.apply(originalConsole, arguments);
        } else {
          var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
          nativeLog(nativeMsg);
        }
    };
}

function uncapture() {
  console.log = originalConsole.log;
}

capture();

After Test

uncapture();

if (typeof functionWithArgs !== "function") { 
  (function() { return "functionWithArgs is not defined"; })();
} else {
  (function() { return logOutput || "console.log never called"; })();
}

Solution

function functionWithArgs(a, b) {
  console.log(a + b);
}
functionWithArgs(10, 5);

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