Simply logging JavaScript calls.

When debugging complicated JavaScript one thing I find myself constantly doing is using console.log() to print out what functions are being called in what order. JavaScript is single-threaded and event driven so it’s often not entirely clear what functions will be called in what order.

Traditionally I’ve done something like this:

function foo(bar) {
  console.log('foo('+bar+')');
}

but last night I came up with something better. It’s probably not completely portable but it seems to work fine in recent Chrome / Safari / Firefox, which is really all I’m going to be using for debugging anyway:

function logCall() {
  console.log(logCall.caller.name + '(' +
    Array.prototype.slice.call(logCall.caller.arguments)
    .map(JSON.stringify).join(', ') + 
    ')');
}

Just add logCall() to the start of functions and the function call (including serialized arguments) will be logged to the console. Easy and foolproof.

One thought on “Simply logging JavaScript calls.

  1. Can you not just set a breakpoint in the js debugger in firebug/chrome dev tools and follow the calls though you get the arguments and ability to live edit code/variables!

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