can-util/js/single-reference/single-reference.js

Common utilities for CanJS projects

"use strict";
var CID = require("can-cid");

var singleReference;

function getKeyName(key, extraKey) {
	var keyCID = key != null && (typeof key === "object" || typeof key === "function") ?
		CID(key) : ""+key;
	var keyName = extraKey ? keyCID + ":" + extraKey : keyCID;
	return keyName || key;
}

// weak maps are slow
/* if(typeof WeakMap !== "undefined") {
	var globalMap = new WeakMap();
	singleReference = {
		set: function(obj, key, value){
			var localMap = globalMap.get(obj);
			if( !localMap ) {
				globalMap.set(obj, localMap = new WeakMap());
			}
			localMap.set(key, value);
		},
		getAndDelete: function(obj, key){
			return globalMap.get(obj).get(key);
		},
		references: globalMap
	};
} else {*/
singleReference = {
    // obj is a function ... we need to place `value` on it so we can retreive it
    // we can't use a global map
    set: function(obj, key, value, extraKey){
        // check if it has a single reference map
        obj[getKeyName(key, extraKey)] = value;
    },

    getAndDelete: function(obj, key, extraKey){
        var keyName = getKeyName(key, extraKey);
        var value = obj[keyName];
        delete obj[keyName];
        return value;
    }
};
/*}*/

module.exports = singleReference;