some useful &.js debugging utils

debug.js

var each = require('amp-each');
var isFunction = require('amp-is-function');

function debugMethods(prototype, handler) {
    each(prototype, function (prop, name) {
        if (isFunction(handler)) return handler(prop, name);
        if (isFunction(prop)) {
            prototype[name] = addLogger(prop, name);
        }
    });
}
exports.debugMethods = debugMethods;

function addLogger(fn, name) {
    return function () {
        console.log('[Function] %s: %o', name, arguments);
        return fn.apply(this, arguments);
    };
}
exports.addLogger = addLogger;

function debugDerived(prototype) {
    debugMethods(prototype._derived, function (prop, name) {
        if (isFunction(prop.fn)) {
            prop.fn = addLogger(prop.fn, name + ':derived');
        }
    });
}
exports.debugDerived = debugDerived;

function mixin(constructor) {
    constructor.debug = function (debugDerived) {
        if (this._debug) return this;
        this._debug = true;
        debugMethods(this.prototype);
        if (debugDerived) debugDerived(this.prototype);
        return this;
    };
}
exports.mixin = mixin;

example.js

var State = require('ampersand-state');
var debugMixin = require('./debug').mixin;

var MyState = module.exports = State.extend({/* my defs here */});

debugMixin(MyState);