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# Example: Basic Caching

The Cache Utility provides a basic caching mechanism for storing key/value pairs in local JavaScript memory.

Cache max: Enforce unique keys:
Data expires after: milliseconds
Key: Value:
Key:
(cache results here)

## Complete Example Source

    <style scoped>
    /* custom styles for this example */
    #demo fieldset {display:block; border:0;}
    #demo .short {width:2em;}
    #out {border:1px solid #CCC; padding:1em}
    </style>

    <form id="demo">
    <fieldset>
        <label for="demo_max">Cache max: <input type="text" id="demo_max" class="short" value="0"> <input type="button" id="demo_setMax" value="Set max"></label>
        <label for="demo_setUniqueKeys">Enforce unique keys: <input type="checkbox" id="demo_setUniqueKeys"></label>
    </fieldset>
    <fieldset>
        <label for="demo_expires">Data expires after: <input type="text" id="demo_expires" class="med" value="86400000"> milliseconds
        <input type="button" id="demo_setExpires" value="Set expires"></label>
    </fieldset>
    <fieldset>
        <label for="demo_addKey">Key: <input type="text" id="demo_addKey"></label>
        <label for="demo_addValue">Value: <input type="text" id="demo_addValue"></label>
        <input type="button" id="demo_add" value="Cache value">
    </fieldset>
    <fieldset>
        <label for="demo_retrieveKey">Key: <input type="text" id="demo_retrieveKey"></label>
        <input type="button" id="demo_retrieve" value="Retrieve value">
    </fieldset>
    <fieldset>
        <input type="button" id="demo_flush" value="Flush cache"></label>
    </fieldset>
    </form>
    <div id="out">(cache results here)</div>

    <script>
    YUI().use("node", "datatype-number", "cache-base", "escape" , function (Y) {
    var cache  = new Y.Cache(),
        out    = Y.one('#out'),
        escape = Y.Escape.html;

    Y.on("click", function(e){
        cache.set("max", Y.DataType.Number.parse(Y.one("#demo_max").get("value")));
        var msg = "Cache max set to " + cache.get("max") + ".";
        out.setHTML(escape(msg)); // Escape user input for example.
    }, "#demo_setMax");

    Y.on("click", function(e){
        cache.set("uniqueKeys", Y.one("#demo_setUniqueKeys").get("checked"));
        var msg = "Cache uniqueKeys set to " + cache.get("uniqueKeys") + ".";
        out.setHTML(escape(msg)); // Escape user input for example.
    }, "#demo_setUniqueKeys");

    Y.on("click", function(e){
        cache.set("expires", Y.DataType.Number.parse(Y.one("#demo_expires").get("value")));
        var msg = "Cache \"expires\" set to " + cache.get("expires") + ".";
        out.setHTML(escape(msg)); // Escape user input for example.
    }, "#demo_setExpires");

    Y.on("click", function(e){
        cache.add(Y.one("#demo_addKey").get("value"), Y.one("#demo_addValue").get("value"));
        var msg = cache.get("max") ?
            "Value cached. Cache size is now " + cache.get("size") + "." :
            "Cache max is " + cache.get("max") + ". Value not cached."
        out.setHTML(escape(msg)); // Escape user input for example.
    }, "#demo_add");

    Y.on("click", function(e){
        var entry = cache.retrieve(Y.one("#demo_retrieveKey").get("value")),
            msg   = entry ? entry.response : "Value not cached.";
        out.setHTML(escape(msg)); // Escape user input for example.
    }, "#demo_retrieve");

    Y.on("click", function(e){
        cache.flush();
        out.setHTML("Cache flushed.");
    }, "#demo_flush");
    });
    </script>