js override console.log if not defined

Question

Which solution do you recommend, the second is simpler ( less code ), but there are drawbacks on using it ?

First: (Set a global debug flag)

// the first line of code
var debug = true;
try {
    console.log
} catch(e) {
    if(e) {
        debug=false;
    }
};
// Then later in the code
if(debug) {
    console.log(something);
}

Second: override console.log

try {
    console.log
} catch(e) {
    if (e) {
        console.log = function() {}
    }
};
// And all you need to do in the code is
console.log(something);

Andy E · Accepted Answer · 2010-09-22T09:55:14.627

56

Neither, but a variation of the second. Lose the try...catch and check for existence of the console object properly:

if (typeof console == "undefined") {
    window.console = {
        log: function () {}
    };
}

console.log("whatever");

edited Sep 22 '10 at 09:55

answered Sep 22 '10 at 09:35

Andy E

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Presumably you either want to do `this.console = ...` or `var console = ...`? As you have it at the moment, you'd get an error in ECMAScript 5 strict mode. – Tim Down Sep 22 '10 at 09:48
1

@Tim: thanks, it was an oversight. I think `window.console` would be best for portability. – Andy E Sep 22 '10 at 09:56
1

Portability in the sense of being able to move this code into a function, rather than portability between environments? – Tim Down Sep 22 '10 at 10:14
1

Should you test typeof window.console since you're setting window.console later? Or should window. be removed? – jcolebrand Oct 25 '11 at 22:54
Definitely check out the solution by Suresh below - he is also defining other console methods that may not be defined. See https://developer.mozilla.org/en-US/docs/Web/API/Console for a full list of all console methods available and what the browser support is like. – Tim Holt Sep 24 '15 at 16:42

score 6 · Answer 2 · answered May 13 '11 at 16:42

6

Or, in coffeescript:

window.console ?=
    log:-> #patch so console.log() never causes error even in IE.

answered May 13 '11 at 16:42

Jameson Quinn

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score 3 · Answer 3 · edited May 23 '17 at 11:50

3

EDIT: Andy's answer is way more elegant than the quick hack I've posted below.

I generally use this approach...

// prevent console errors on browsers without firebug
if (!window.console) {
    window.console = {};
    window.console.log = function(){};
}

edited May 23 '17 at 11:50

Community

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1

answered Sep 22 '10 at 09:40

Frankie

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I like your version Frankie, but I'm not sure that it works safely across all browsers. I remember using this and still getting occasional issues with one of the IE versions, perhaps because `console` object is only defined when the console window is open in IE9. I think I had to do an 'undefined' check like Andy E suggested. – Simon East Sep 23 '11 at 02:58
@Simon this comes late as a comment but only saw it today. Andy's solution is way more elegant than this quick hack I've posted. You should use that instead. – Frankie Jun 15 '13 at 16:34

score 1 · Answer 4 · edited Feb 16 '16 at 15:53

1

I've faced a similar bug in my past, and I overcame it with the code below:

if(!window.console) {
    var console = {
        log : function(){},
        warn : function(){},
        error : function(){},
        time : function(){},
        timeEnd : function(){}
    }
}

edited Feb 16 '16 at 15:53

Community

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1

answered Jun 17 '14 at 10:29

Suresh

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How is this different than Frankie or Andy_E answers ? – Radu Maris Jun 17 '14 at 13:23
The answer by Suresh is better in that he is also defining other methods that will not be defined along with log. Check out https://developer.mozilla.org/en-US/docs/Web/API/Console for a full list of all functions that may (or may not) be defined. – Tim Holt Sep 24 '15 at 16:40
This won't work if it's called from within a function. Instead of `var console` it should be `window.console` or just `console` – Glenn Lawrence Nov 11 '15 at 10:54

score 0 · Answer 5 · answered Jun 19 '12 at 21:27

0

I came across this post, which is similar to the other answers:

http://jennyandlih.com/resolved-logging-firebug-console-breaks-ie

answered Jun 19 '12 at 21:27

David

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score 0 · Answer 6 · answered Nov 23 '12 at 21:47

0

The following will achieve what you are looking for:

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

answered Nov 23 '12 at 21:47

Mike Kormendy

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score 0 · Answer 7 · answered Jul 18 '13 at 17:31

0

window.console = window.console || {};
window.console.log = window.console.log || function() {};

answered Jul 18 '13 at 17:31

Sean

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js override console.log if not defined

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