The beginning of a standard library for javascript

standard.js

/* The beginning of a standard library */

Array.prototype.indexOf = function (obj, pos, compareFn) {
    var pos = pos || 0;
    
    compareFn = compareFn || function(obj1, obj2) { return obj1 == obj2; };
    
    for (; pos < this.length; pos++) {
        if (compareFn(obj, this[pos])) { return pos; }
    }
    return -1;
};

Array.prototype.lastIndexOf = function (obj, pos) {
    var pos = pos || this.length - 1;
    for (; pos >= 0; pos--) {
        if (obj === this[pos]) { return pos; }
    }
    return -1;
};

Array.prototype.add = function () {
    var i = 0;
    for (; i < arguments.length; i++) {
        if (this.indexOf(arguments[i]) === -1) { this.push(arguments[i]); }
    }
};

Array.prototype.remove = function (obj) {
    var index;
    
    while ((index = this.indexOf(obj)) !== -1) {
        this.splice(index, 1);
    }
    
    return this;
};

Object.size = function (obj, includeFns) {
    var size = 0, key;
    for (key in obj) {
        if (obj.hasOwnProperty(key) && (!includeFns || typeof obj[key] == 'function')) { size++; }
    }
    return size;
};

Object.toArray = function (obj) {
    var coll = [], key;
    for (key in obj) {
        if (obj.hasOwnProperty(key) && typeof obj[key] !== 'function') {
            coll.push({ key: key, value: obj[key] });
        }
    }
    return coll;
};

Object.isType = function (obj, type) {
    return (obj.constructor === type);
}

String.prototype.format = function () {
    var formatted = this, i = 0, regexp;
    for (; i < arguments.length; i++) {
        regexp = new RegExp('\\{' + i + '\\}', 'gi');
        formatted = formatted.replace(regexp, arguments[i]);
    }
    return formatted;
};