falcor/lib/get/getCache.js

A JavaScript library for efficient data fetching.

var isInternalKey = require("./../support/isInternalKey");

/**
 * decends and copies the cache.
 */
module.exports = function getCache(cache) {
    var out = {};
    _copyCache(cache, out);

    return out;
};

function cloneBoxedValue(boxedValue) {
    var clonedValue = {};

    var keys = Object.keys(boxedValue);
    var key;
    var i;
    var l;

    for (i = 0, l = keys.length; i < l; i++) {
        key = keys[i];

        if (!isInternalKey(key)) {
            clonedValue[key] = boxedValue[key];
        }
    }

    return clonedValue;
}

function _copyCache(node, out, fromKey) {
    // copy and return

    Object.
        keys(node).
        filter(function(k) {
            // Its not an internal key and the node has a value.  In the cache
            // there are 3 possibilities for values.
            // 1: A branch node.
            // 2: A $type-value node.
            // 3: undefined
            // We will strip out 3
            return !isInternalKey(k) && node[k] !== undefined;
        }).
        forEach(function(key) {
            var cacheNext = node[key];
            var outNext = out[key];

            if (!outNext) {
                outNext = out[key] = {};
            }

            // Paste the node into the out cache.
            if (cacheNext.$type) {
                var isObject = cacheNext.value && typeof cacheNext.value === "object";
                var isUserCreatedcacheNext = !cacheNext.$_modelCreated;
                var value;
                if (isObject || isUserCreatedcacheNext) {
                    value = cloneBoxedValue(cacheNext);
                } else {
                    value = cacheNext.value;
                }

                out[key] = value;
                return;
            }

            _copyCache(cacheNext, outNext, key);
        });
}