function transform(coll, accumulator, iteratee, callback) {
    if (arguments.length <= 3) {
        callback = iteratee;
        iteratee = accumulator;
        accumulator = (0, _isArray2.default)(coll) ? [] : {};
    }
    callback = (0, _once2.default)(callback || _noop2.default);
    var _iteratee = (0, _wrapAsync2.default)(iteratee);

    (0, _eachOf2.default)(coll, function (v, k, cb) {
        _iteratee(accumulator, v, k, cb);
    }, function (err) {
        callback(err, accumulator);
    });
}
/**
 * A relative of `reduce`.  Takes an Object or Array, and iterates over each
 * element in series, each step potentially mutating an `accumulator` value.
 * The type of the accumulator defaults to the type of collection passed in.
 *
 * @name transform
 * @static
 * @memberOf module:Collections
 * @method
 * @category Collection
 * @param {Array|Iterable|Object} coll - A collection to iterate over.
 * @param {*} [accumulator] - The initial state of the transform.  If omitted,
 * it will default to an empty Object or Array, depending on the type of `coll`
 * @param {AsyncFunction} iteratee - A function applied to each item in the
 * collection that potentially modifies the accumulator.
 * Invoked with (accumulator, item, key, callback).
 * @param {Function} [callback] - A callback which is called after all the
 * `iteratee` functions have finished. Result is the transformed accumulator.
 * Invoked with (err, result).
 * @example
 *
 * async.transform([1,2,3], function(acc, item, index, callback) {
 *     // pointless async:
 *     process.nextTick(function() {
 *         acc.push(item * 2)
 *         callback(null)
 *     });
 * }, function(err, result) {
 *     // result is now equal to [2, 4, 6]
 * });
 *
 * @example
 *
 * async.transform({a: 1, b: 2, c: 3}, function (obj, val, key, callback) {
 *     setImmediate(function () {
 *         obj[key] = val * 2;
 *         callback();
 *     })
 * }, function (err, result) {
 *     // result is equal to {a: 2, b: 4, c: 6}
 * })
 */
A relative of `reduce`.  Takes an Object or Array, and iterates over each
element in series, each step potentially mutating an `accumulator` value.
The type of the accumulator defaults to the type of collection passed in.





@example


A relative of ` reduce ` . Takes an Object or Array and iterates over each element in series each step potentially mutating an ` accumulator ` value . The type of the accumulator defaults to the type of collection passed in . @example
function transform(coll, accumulator, iteratee, callback) {
    if (arguments.length <= 3) {
        callback = iteratee;
        iteratee = accumulator;
        accumulator = (0, _isArray2.default)(coll) ? [] : {};
    }
    callback = (0, _once2.default)(callback || _noop2.default);
    var _iteratee = (0, _wrapAsync2.default)(iteratee);
    (0, _eachOf2.default)(coll, function (v, k, cb) {
        _iteratee(accumulator, v, k, cb);
    }, function (err) {
        callback(err, accumulator);
    });
}
function transform ( coll , accumulator , iteratee , callback ) { if ( arguments . length <= 3 ) { callback = iteratee ; iteratee = accumulator ; accumulator = ( 0 , _isArray2 . default ) ( coll ) ? [ ] : { } ; } callback = ( 0 , _once2 . default ) ( callback || _noop2 . default ) ; var _iteratee = ( 0 , _wrapAsync2 . default ) ( iteratee ) ; ( 0 , _eachOf2 . default ) ( coll , function ( v , k , cb ) { _iteratee ( accumulator , v , k , cb ) ; } , function ( err ) { callback ( err , accumulator ) ; } ) ; }
A relative of `reduce`.
A relative of ` reduce ` .