Javascript Core Utils

core_extensions.js

/*
 * Copyright 2009 Wilker Lucio <wilkerlucio@gmail.com>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. 
 */

/**
 * This file contains a series of common used extensions for Javascript
 */

//object extensions
Object.extend = function(target, mixin, send_attributes) {
	for (var p in mixin) {
		target[p] = mixin[p];
	}
	
	return target;
};

Object.extend(Object, {
	alias: function(target, original, alias) {
		target[alias] = target[original];
		
		return target;
	},
	
	is_array: function(object) {
		return object != null && typeof object == "object" && 'splice' in object && 'join' in object;
	},
	
	is_function: function(is_function) {
		return typeof object == "function";
	}
});

//enumerable
Enumerable = {
	all: function(iterator) {
		var all = true;
		
		this.each(function(value) {
			if (!iterator(value)) {
				all = false;
				return false;
			}
		});
		
		return all;
	},
	
	any: function(iterator) {
		var any = false;
		
		this.each(function(value) {
			if (iterator(value)) {
				any = true;
				return false;
			}
		});
		
		return any;
	},
	
	find: function(iterator) {
		var element = null;
		
		this.each(function(value) {
			if (iterator(value)) {
				element = value;
				return false;
			}
		});
		
		return element;
	},
	
	find_all: function(iterator) {
		var elements = [];
		
		this.each(function(value) {
			if (iterator(value)) {
				elements.push(value);
			}
		});
		
		return elements;
	},
	
	include: function(element) {
		var include = false;
		
		this.each(function(value) {
			if (element == value) {
				include = true;
				return false;
			}
		});
		
		return include;
	},
	
	inject: function(iterator, first) {
		first = first || null;
		
		this.each(function(value) {
			first = iterator(first, value);
		});
		
		return first;
	},
	
	invoke: function() {
		var args = $A(arguments);
		var method = args.shift();
		
		return this.map(function(value) {
			return value[method].apply(value, args);
		});
	},
	
	map: function(iterator) {
		var mapped = [];
		
		this.each(function(value, key) {
			mapped.push(iterator(value, key));
		});
		
		return mapped;
	},
	
	partition: function(iterator) {
		var accept = [];
		var reject = [];
		
		this.each(function(value) {
			if (iterator(value)) {
				accept.push(value);
			} else {
				reject.push(value);
			}
		});
		
		return [accept, reject];
	},
	
	pluck: function(property) {
		return this.map(function(value) {
			return value[property];
		});
	},
	
	reject: function(iterator) {
		var elements = [];
		
		this.each(function(value) {
			if (!iterator(value)) {
				elements.push(value);
			}
		});
		
		return elements;
	},
	
	sort_by: function(criteria) {
		return $A(this).sort(function(a, b) {
			a = a[criteria];
			b = b[criteria];
			
			if (Object.is_function(a)) a = a();
			if (Object.is_function(b)) b = b();
			
			return a > b ? 1 : (a < b ? -1 : 0);
		});
	},
	
	zip: function() {
		var items = $A(arguments);
		var iterator = items.shift();
		var results = [];
		
		items.unshift($A(this));
		
		for (var i = 0; i < items[0].length; i++) {
			var line = [];
			
			for (var x = 0; x < items.length; x++) {
				line.push(items[x][i]);
			}
			
			results.push(iterator.apply(this, line));
		}
		
		return results;
	}
};

Object.alias(Enumerable, 'map', 'collect');
Object.alias(Enumerable, 'include', 'member');
Object.alias(Enumerable, 'find', 'detect');
Object.alias(Enumerable, 'find_all', 'select');

//array extensions
Object.extend(Array.prototype, Enumerable);

Array.prototype.each = function(iterator) {
	for (var i = 0; i < this.length; i++) {
		if (!iterator(this[i])) break;
	}
	
	return this;
}

Array.to_a = function(enumerable) {
	var array = [];
	
	for (var i = 0; i < enumerable; i++) {
		array.push(enumerable[i]);
	}
	
	return array;
};

$A = Array.to_a();

//function extensions
Object.extend(Function.prototype, {
	bind: function() {
		if (arguments.length < 2 && Object.isUndefined(arguments[0])) return this;
		var __method = this, args = $A(arguments), object = args.shift();
		return function() {
			return __method.apply(object, args.concat($A(arguments)));
		};
	},

	bindAsEventListener: function() {
		var __method = this, args = $A(arguments), object = args.shift();
		return function(event) {
			return __method.apply(object, [event || window.event].concat(args));
		};
	},

	curry: function() {
		if (!arguments.length) return this;
		var __method = this, args = $A(arguments);
		return function() {
			return __method.apply(this, args.concat($A(arguments)));
		};
	},

	delay: function() {
		var __method = this, args = $A(arguments), timeout = args.shift() * 1000;
		return window.setTimeout(function() {
			return __method.apply(__method, args);
		}, timeout);
	},

	defer: function() {
		var args = [0.01].concat($A(arguments));
		return this.delay.apply(this, args);
	}
});