goodparts6.js

Function.prototype.method = function (name, func) {
	if (!this.prototype[name]) {
		this.prototype[name] = func;
		return this;
	}
};

Array.method('reduce', function (f, value) {
	var i;
	for (i = 0; i < this.length; i+= 1) {
		value = f(this[i].value);
	}
});

var data = [4, 8, 15, 16, 23, 42];
var add = function (a, b) {
	return a + b;
};
var mult = function (a, b) {
	return a * b;
};
var sum = data.reduce(add, 0);
data.total = function () {
	return this.reduce(add, 0);
};


// 6.7
Array.dim = function (dimention, initial) {
	var a = [], i;
	for ( i = 0; i < dimention; i += 1) {
		a[i] = initial;
	}
	return a;
};
var myArray = Array.dim(10, 0);
var matrix = [
	[0, 1, 2],
	[3, 4, 5],
	[6, 7, 8]
];
for (i = 0; i < n; i += 1) {
	my_array[i] = [];
}
Array.matrix = function (m, n, initial) {
	var a, i, j, mat = [];
	for (i = 0; i < m; i += 1) {
		a = [];
		for (j = 0; j < n; j += 1) {
			a[j] = initial;
		}
		mat[i] = a;
	}
	return mat;
}
var myMatrix = Array.matrix(4, 4, 0);
Array.identity = function (n) {
	var i, mat = Array.matrix(n, n, 0);
	for (i = 0; i < n; i += 1) {
		mat[i][i] = 1;
	}
	return mat;
};
myMatrix = Array.identity(4);