Javascript - Cache function result

js-cache-function-result.js

// http://www.sitekickr.com/blog/?p=946&preview=true

function Cache() {
    // create the cache object as a singleton (only one instance allowed)
    if(typeof Cache.instance === 'undefined') {
        Cache.instance = this;
    }

    var data = [ ]

    // we'll abbreviate cacheAwareCall as caCall
    this.caCall = function(functionName) {
        var cacheCheck = this.load(functionName, this.caCall.arguments);

        if (typeof cacheCheck !== 'undefined') {
            return cacheCheck;
        else {
            var returnValue = window[functionName].apply(this, this.caCall.arguments)
            this.save(functionName, this.caCall.arguments, returnValue);
            return returnValue;
        }
    }

    this.save = function(functionName, argumentObject, returnValue) {
        // prepend item to cache
        data.unshift({ fname: functionName, arguments: argumentObject, returnValue: returnValue });
    }

    this.load = function(functionName, argumentObject) {
        for(entry in data) {
            if(data[entry]['fname'] === functionName) {
                // we have a match on the function name
                // deepCompare is not implemented here, examples are throughout the web
                if(deepCompare(argumentObject, data[entry]['arguments']) {
                    return data[entry]['returnValue'];
                }
            }
        }

        return undefined;
    }

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    return Cache.instance;
}