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var baseCallback = require('./baseCallback'),
baseEach = require('./baseEach'),
isArray = require('../lang/isArray');
/**
* Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
*
* @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;
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