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var arrayEach = require('../internal/arrayEach'),
baseCallback = require('../internal/baseCallback'),
baseCreate = require('../internal/baseCreate'),
baseForOwn = require('../internal/baseForOwn'),
isArray = require('../lang/isArray'),
isFunction = require('../lang/isFunction'),
isObject = require('../lang/isObject'),
isTypedArray = require('../lang/isTypedArray');
/**
* An alternative to `_.reduce`; this method transforms `object` to a new
* `accumulator` object which is the result of running each of its own enumerable
* properties through `iteratee`, with each invocation potentially mutating
* the `accumulator` object. The `iteratee` is bound to `thisArg` and invoked
* with four arguments: (accumulator, value, key, object). Iteratee functions
* may exit iteration early by explicitly returning `false`.
*
* @static
* @memberOf _
* @category Object
* @param {Array|Object} object The object to iterate over.
* @param {Function} [iteratee=_.identity] The function invoked per iteration.
* @param {*} [accumulator] The custom accumulator value.
* @param {*} [thisArg] The `this` binding of `iteratee`.
* @returns {*} Returns the accumulated value.
* @example
*
* _.transform([2, 3, 4], function(result, n) {
* result.push(n *= n);
* return n % 2 == 0;
* });
* // => [4, 9]
*
* _.transform({ 'a': 1, 'b': 2 }, function(result, n, key) {
* result[key] = n * 3;
* });
* // => { 'a': 3, 'b': 6 }
*/
function transform(object, iteratee, accumulator, thisArg) {
var isArr = isArray(object) || isTypedArray(object);
iteratee = baseCallback(iteratee, thisArg, 4);
if (accumulator == null) {
if (isArr || isObject(object)) {
var Ctor = object.constructor;
if (isArr) {
accumulator = isArray(object) ? new Ctor : [];
} else {
accumulator = baseCreate(isFunction(Ctor) ? Ctor.prototype : undefined);
}
} else {
accumulator = {};
}
}
(isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
return iteratee(accumulator, value, index, object);
});
return accumulator;
}
module.exports = transform;
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