js debug console

03 October 2006 // javascript. things.

Debug Console is a small utility for printing debug messages on the "console". Console is simply a textarea hanging in the corner of the page. No popups, no fancy formatting, but simple, clean and cross-browser.

Console also provides utility functions for printing stack trace and for measuring execution speed.

download js file

Here's what the Console can do (feel free to click "try it" links, to hide the console reload the page).

p() -- print multiple arguments

p('hello', 99, ['a', 'b', 'c'], window.noSuchObject);

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// whitespaces are "visible"

p('a line \n with tabs\t\t and spaces\t and tabs');

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// trace nested array

ary = [1, 2, [33, [444, 555], 66], 7]
p(ary);

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pp() -- print a single structured object

// second argument is a maximal depth (negative = infinite)
// by default, functions are not traced

var person = {
    name : 'John', age : 33,
    occupation : {
        type : 'programmer',
        skills : {
            php : 'good',
            js : 'expert',
            ruby : 'poor'
        },
        points: [1, 2, [33, 44], 5]
    },
    someMethod: function() { alert('Hi') }
}
pp(person, -1);

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// pp() is able to break infinite recursion

var ring = {
    a: 1, b: 2, c: 3
}
ring.self = ring
pp(ring, -1);

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// trace DOM node (default recursion depth 1 recommended)

pp(document.body);

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dbgc "API"

Dbgc.print('Hello')

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Dbgc.trace('Hello')

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Dbgc.clear()

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Dbgc.close()

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alert(Dbgc.inspect('Hello'))

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miscellaneous

// time()
// measure execution time

function foo() {
    for(var i = 0; i != 500; i++)
        Math.sin(i)
}
Dbgc.print(Dbgc.time(foo))

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// stack()
// print stack trace

function a(x, y, z) {
    Dbgc.stack();
}
function b(one, two) {
    a(11, 22, 33);
}
function c() {
    b('aa', 'bb');
}
c()

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