Function createAggregator

test-app/public/sinon.js:15449–15456

* Creates a function like `_.groupBy`. * * @private * @param {Function} setter The function to set accumulator values. * @param {Function} [initializer] The accumulator object initializer. * @returns {Function} Returns the new aggregator function.

(setter, initializer)

         * @returns {Function} Returns the new aggregator function.
         */
        function createAggregator(setter, initializer) {
          return function(collection, iteratee) {
            var func = isArray(collection) ? arrayAggregator : baseAggregator,
                accumulator = initializer ? initializer() : {};
    
            return func(collection, setter, getIteratee(iteratee, 2), accumulator);
          };
        }
    
        /**
         * Creates a function like `_.assign`.