freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/basic-javascript/local-scope-and-functions.chinese.md

id, title, challengeType, videoUrl, localeTitle

id	title	challengeType	videoUrl	localeTitle
56533eb9ac21ba0edf2244bf	Local Scope and Functions	1		本地范围和功能

Description

在函数内声明的变量，以及函数参数都具有局部范围。这意味着，它们仅在该功能中可见。这是一个函数myTest带有一个名为loc的局部变量。

function myTest（）{
var loc =“foo”;
的console.log（LOC）;
}
MYTEST（）; //记录“foo”
的console.log（LOC）; // loc未定义

loc未在函数外定义。

Instructions

在myLocalScope声明一个局部变量myVar 。运行测试，然后按照编辑器中注释的说明进行操作。 暗示
如果您遇到问题，刷新页面可能会有所帮助。

Tests

tests:
  - text: 没有全局<code>myVar</code>变量
    testString: 'assert(typeof myVar === "undefined", "No global <code>myVar</code> variable");'
  - text: 添加本地<code>myVar</code>变量
    testString: 'assert(/var\s+myVar/.test(code), "Add a local <code>myVar</code> variable");'

Challenge Seed

function myLocalScope() {
  'use strict'; // you shouldn't need to edit this line

  console.log(myVar);
}
myLocalScope();

// Run and check the console
// myVar is not defined outside of myLocalScope
console.log(myVar);

// Now remove the console log line to pass the test

Before Test

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

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

After Test

console.info('after the test');

Solution

// solution required