Pass arguments to console.log as first class arguments via proxy function
JavascriptJavascript Problem Overview
console.log
takes an unspecified number of arguments and dumps their content in a single line.
Is there a way I can write a function that passes arguments passed to it directly to console.log
to maintain that behaviour? For example:
function log(){
if(console){
/* code here */
}
}
This would not be the same as:
function log(){
if(console){
console.log(arguments);
}
}
Since arguments
is an array and console.log
will dump the contents of that array. Nor will it be the same as:
function log(){
if(console){
for(i=0;i<arguments.length;console.log(arguments[i]),i++);
}
}
Since that will print everything in different lines. The point is to maintain console.log
's behaviour, but through a proxy function log
.
+---
I was looking for a solution I could apply to all functions in the future (create a proxy for a function keeping the handling of arguments intact). If that can't be done however, I'll accept a console.log
specific answer.
Javascript Solutions
Solution 1 - Javascript
This should do it ..
function log() {
if(typeof(console) !== 'undefined') {
console.log.apply(console, arguments);
}
}
Just adding another option (using the spread operator and the rest parameters - although arguments
could be used directly with the spread)
function log(...args) {
if(typeof(console) !== 'undefined') {
console.log(...args);
}
}
Solution 2 - Javascript
There is a good example from the html5boilerplate code that wraps console.log in a similar way to make sure you don't disrupt any browsers that don't recognize it. It also adds a history and smoothes out any differences in the console.log implementation.
It was developed by Paul Irish and he has written up a post on it here.
I've pasted the relevant code below, here is a link to the file in the project: https://github.com/h5bp/html5-boilerplate/blob/master/js/plugins.js
// usage: log('inside coolFunc', this, arguments);
// paulirish.com/2009/log-a-lightweight-wrapper-for-consolelog/
window.log = function(){
log.history = log.history || []; // store logs to an array for reference
log.history.push(arguments);
if(this.console) {
arguments.callee = arguments.callee.caller;
var newarr = [].slice.call(arguments);
(typeof console.log === 'object' ? log.apply.call(console.log, console, newarr) : console.log.apply(console, newarr));
}
};
// make it safe to use console.log always
(function(b){function c(){}for(var d="assert,count,debug,dir,dirxml,error,exception,group,groupCollapsed,groupEnd,info,log,timeStamp,profile,profileEnd,time,timeEnd,trace,warn".split(","),a;a=d.pop();){b[a]=b[a]||c}}((function(){try {console.log();return window.console;}catch(err){return window.console={};}})());
Solution 3 - Javascript
Yes.
console.log.apply(null,arguments);
Although, you may need to loop through the arguments object and create a regular array from it, but apart from that that's how you do it.