LINQ-style Javascript Array Extensions

linq.js

Array.prototype.sum = function (selector) {
    var source = this;
    var totalSum = 0;

    for (var i = 0; i < source.length; i++) {
        totalSum += selector(source[i]);
    }

    return totalSum;
};

Array.prototype.select = function (selector) {
    var source = this;
    var array = [];

    for (var i = 0; i < source.length; i++) {
        array.push(selector(source[i]));
    }

    return array;
};

Array.prototype.selectMany = function (selector) {
    var source = this;
    var array = [];

    for (var i = 0; i < source.length; i++) {
        var innerArray = selector(source[i]);
        if (innerArray.length) {
            for (var j = 0; j < innerArray.length; j++) {
                array.push(innerArray[j]);
            }
        }
    }

    return array;
};

Array.prototype.contains = function (item) {
    var source = this;

    for (var i = 0; i < source.length; i++) {
        if (source[i] === item) {
            return true;
        }
    }

    return false;
};

Array.prototype.all = function (expression) {
    var source = this;
    var success = true;

    for (var i = 0; i < source.length; i++) {
        success = success && expression(source[i]);
    }

    return success;
};

Array.prototype.any = function (expression) {
    if (expression === undefined) {
        return this.length > 0;
    }

    var source = this;

    for (var i = 0; i < source.length; i++) {
        if (expression(source[i])) {
            return true;
        }
    }

    return false;
};

Array.prototype.where = function (expression) {
    var source = this;
    var array = [];

    for (var i = 0; i < source.length; i++) {
        if (expression(source[i])) {
            array.push(source[i]);
        }
    }

    return array;
};

Array.prototype.first = function (expression) {
    var source = this,
        result = source.where(expression);
    
    return result.length > 0 ? result[0] : null;
};

Array.prototype.groupBy = function (selector) {
    var source = this;
    var array = [];

    for (var i = 0; i < source.length; i++) {
        var item = array.first(function (n) { return equalData(n.key, selector(source[i])); });
        if (item === null) {
            item = [];
            item.key = selector(source[i]);
            array.push(item);
        }
        
        item.push(source[i]);
    }

    return array;

    function equalData(c, x) {
        // date compare
        if (c instanceof Date && x instanceof Date) {
            return c.getTime() == x.getTime();
        }

        if (c instanceof Date != x instanceof Date) {
            return false;
        }

        // type compare
        if (typeof c !== typeof x) {
            return false;
        }

        // number or string compare
        if (typeof c === "number" || typeof c === "string") {
            return c === x;
        }

        // object properties compare
        for (var key in c) {
            if (c[key] !== x[key]) {
                return false;
            }
        }

        // all seems to be right
        return true;
    }
};

Array.prototype.indexOf = Array.prototype.indexOf || function (elt /*, from*/) {
    var len = this.length >>> 0;

    var from = Number(arguments[1]) || 0;
    from = (from < 0) ? Math.ceil(from) : Math.floor(from);

    if (from < 0) {
        from += len;
    }

    for (; from < len; from++) {
        if (from in this && this[from] === elt) {
            return from;
        }
    }

    return -1;
};

Array.prototype.getType = function (selector) {
    if (this.length == 0) return "undefined";

    for (var i = 0; i < this.length; i++) {
        var type = typeof selector(this[i]);
        if (type == "number") return "number";
        if (type == "string") return "string";
        if (type == "boolean") return "boolean";
        if (selector(this[i]) instanceof Date) return "Date";
    }

    return "undefined";
}

Array.prototype.orderBy = function (selector) {
    if (this.length == 0) return;

    var type = this.getType(selector);
    if (type == "number") {
        return this.sort(function (a, b) { return selector(a) - selector(b); });
    }
    else if (type == "string") {
        return this.sort(function (a, b) {
            var x = selector(a) || "",
                y = selector(b) || "";

            return x < y ? -1 : (x > y ? 1 : 0);
        });
    }
    else if (type == "boolean") {
        return this.sort(function (a, b) { return selector(a) == selector(b) ? 1 : -1 });
    }
    else if (type == "Date") {
        return this.sort(function (a, b) { return (selector(a) || new Date(0)).getTime() - (selector(b) || new Date(0)).getTime(); });
    }
    else {
        return this;
    }
}

Array.prototype.orderByDescending = function (selector) {
    if (this.length == 0) return;

    var type = this.getType(selector);
    if (type == "number") {
        return this.sort(function (b, a) { return selector(a) - selector(b); });
    }
    else if (type == "string") {
        return this.sort(function (b, a) {
            var x = selector(a) || "",
                y = selector(b) || "";

            return x < y ? -1 : (x > y ? 1 : 0);
        });
    }
    else if (type == "boolean") {
        return this.sort(function (b, a) { return selector(a) == selector(b) ? -1 : 1 });;
    }
    else if (type == "Date") {
        return this.sort(function (b, a) { return (selector(a) || new Date(0)).getTime() - (selector(b) || new Date(0)).getTime(); });
    }
    else {
        return this;
    }
}

Oh, and its deprecated. Use this happy library instead