在 IE 中测试 console.log 语句 [英] Testing for console.log statements in IE

问题描述

可能的重复:
'console' 是 Internet Explorer 的未定义错误

如果您的代码中有 console.log 语句，Internet Explorer 将抛出 JavaScript 错误(至少在我们的内网用户安装的 IE7 中).

If you have console.log statements in your code, Internet Explorer will throw a JavaScript error (at least in IE7 which is what our intranet users have installed).

我使用 Firefox 进行大部分开发测试，主要是因为 Firebug 提供的功能(我在其中使用了大量控制台语句)，但我也需要在 IE 中进行测试.

I am using Firefox for most of my development testing primarily because of the functionality provided by Firebug (where I use a lot of console statements) but I also need to test in IE.

如果我将以下内容添加到我的 JavaScript 中，则不会抛出错误.

if I add the following to my JavaScript, the error does not get thrown.

var debugging = false;
if (typeof console == "undefined") 
    var console = { log: function() {} };  

问题是如果调试模式为假，我想触发一个事件.如果我创建一个函数来测试调试是否为 false 并执行一个操作(此时只是一个警报)，但是当我尝试执行以下操作时，我收到一个 IE 错误，提示 控制台未定义.>

The problem is that I would like to trigger an event if debugging mode is false. If I create a function to test whether debugging is false and do an action (at this point just an alert) but when I try do the following I receive an IE error saying Console is not defined.

var debugging = false; // or true   
if (typeof console == "undefined") 
    var console = { log: function() {consoleMsg()} };   

function consoleMsg() {
    if(!debugging) {
    alert('Console.log event in Production Code');
}   

如果有人可以帮助我修复代码、提供更好的方法来帮助我实现目标，或者将我引导到资源来教育自己，我将不胜感激.

If someone could help me to fix my code, provide a better way to help me achieve my goal, or direct me to a resource to edumacate myself I would be very appreciative.

推荐答案

您不必跳过所有这些障碍.只需在使用前检查控制台是否存在即可.

You don't have to jump through all these hoops. Simply check if the console exists before using it.

所以，而不是:

console.log('foo');

使用:

window.console && console.log('foo');

...你不会得到任何错误.

...and you won't get any errors.

或者，您可以在脚本的顶部检查它，如果它未定义，只需用一个空函数填充它:

Alternatively, you could just check for it at the top of your script, and if it's undefined, just fill it with an empty function:

// At the top of your script:
if ( ! window.console ) console = { log: function(){} };
// If you use other console methods, add them to the object literal above

// Then, anywhere in your script:
console.log('This message will be logged, but will not cause an error in IE7');

<小时>

要获得更强大的解决方案，请使用这段代码(取自 twitter 的源代码):

---

For a more robust solution, use this piece of code (taken from twitter's source code):

// Avoid `console` errors in browsers that lack a console.
(function() {
    var method;
    var noop = function () {};
    var methods = [
        'assert', 'clear', 'count', 'debug', 'dir', 'dirxml', 'error',
        'exception', 'group', 'groupCollapsed', 'groupEnd', 'info', 'log',
        'markTimeline', 'profile', 'profileEnd', 'table', 'time', 'timeEnd',
        'timeStamp', 'trace', 'warn'
    ];
    var length = methods.length;
    var console = (window.console = window.console || {});

    while (length--) {
        method = methods[length];

        // Only stub undefined methods.
        if (!console[method]) {
            console[method] = noop;
        }
    }
}());

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