Tuesday, December 23rd, 2008
Thomas Fuchs comes back with some JavaScript tips
Category: JavaScript
Preventing console.log breakage
We have all been there. After a serious Firebug session, you forget to take out the console statements. Or, maybe you like to keep them in for the future. To be sure, you can redefine some no-ops:
JAVASCRIPT:
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f(window['console'] === undefined)
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window.console = { log: Prototype.emptyFunction };
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To not rely on Prototype, you can simply log: function() {}.
Kangax then shared his approach:
JAVASCRIPT:
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(function(__global){
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if (!__global.console || (__global.console && !__global.console.log)) {
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__global.console = {
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log: (__global.opera && __global.opera.postError)
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? __global.opera.postError
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: function(){ }
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}
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}
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})(this);
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In this tip, Thomas talks about how he likes to use a little curry to reuse the same code in different ways.
For example, taking a generic page turner:
JAVASCRIPT:
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// pages are numbered from 1 to 10
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var currentPage = 1, pageCount = 10;
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function turnPage(dir){
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currentPage += dir || 0;
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currentPage =
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(currentPage == 0) ? pageCount :
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(currentPage == pageCount+1) ? 1 : currentPage;
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// here we would do whatever is necessary to render
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}
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and currying some helpers:
JAVASCRIPT:
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var nextPage = turnPage.curry(1),
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previousPage = turnPage.curry(-1);
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Although the examples are using Prototype, other libraries have the equivalent curry power.
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2.6 rating from 19 votes
Funny, I noticed this problem the other day and came up with a similar solution:
if(!console) conole = {log: function(){return false}}
SnoreFest2008 RoundUp Extreme++!!!
if i wanted javascript tips i’d go to javascript.about.com.
I avoid console.log(), typing that is cumbersome in the middle of a frenetic debugging session! Instead I use a log() facade.
function log() { if (console) console.log.apply(console, arguments); }
See http://jaybyjayfresh.com/2008/11/10/consolelog-in-safari-doesnt-apply-bad-safari/