Memoization Pattern From 'JavaScript Patterns' (O'Reilly) by Stoyan Stefanov.

Memoization Pattern.js

/* Memoization Pattern */

// a single parameter example
var myFunc = function ( param ) {
	if ( !myFunc.cache[ param ] ) {
		var result = {};
		// ... expensive operation ...
		myFunc.cache[ param ] = result;
	}
	return myFunc.cache[ param ];
};
// cache storage
myFunc.cache = {};

// a multiple params solution
var myFunc = function () {
	// serialize the params as a JSON string
	var cachekey = JSON.stringify( Array.prototype.slice.call( arguments ) ),
		result;
	if ( !myFunc.cache[ param ] ) {
		result = {};
		// ... expensive operation ...
		myFunc.cache[ cachekey ] = result;
	}
	return myFunc.cache[ cachekey ];
};
// cache storage
myFunc.cache = {};