compound-ex4
Version:
Compound-ex4 - MVC framework for NodeJS (ExpressJs 4 version), fork compoundjs(https://github.com/1602/compound)
41 lines (36 loc) • 1.36 kB
JavaScript
var baseCallback = require('./baseCallback'),
baseEach = require('./baseEach'),
isArray = require('../lang/isArray');
/**
* Creates a function that aggregates a collection, creating an accumulator
* object composed from the results of running each element in the collection
* through an iteratee.
*
* **Note:** This function is used to create `_.countBy`, `_.groupBy`, `_.indexBy`,
* and `_.partition`.
*
* @private
* @param {Function} setter The function to set keys and values of the accumulator object.
* @param {Function} [initializer] The function to initialize the accumulator object.
* @returns {Function} Returns the new aggregator function.
*/
function createAggregator(setter, initializer) {
return function(collection, iteratee, thisArg) {
var result = initializer ? initializer() : {};
iteratee = baseCallback(iteratee, thisArg, 3);
if (isArray(collection)) {
var index = -1,
length = collection.length;
while (++index < length) {
var value = collection[index];
setter(result, value, iteratee(value, index, collection), collection);
}
} else {
baseEach(collection, function(value, key, collection) {
setter(result, value, iteratee(value, key, collection), collection);
});
}
return result;
};
}
module.exports = createAggregator;