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intersectionBy.js
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intersectionBy.js
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define(['./_arrayMap', './_baseIntersection', './_baseIteratee', './_baseRest', './_castArrayLikeObject', './last'], function(arrayMap, baseIntersection, baseIteratee, baseRest, castArrayLikeObject, last) {
/** Used as a safe reference for `undefined` in pre-ES5 environments. */
var undefined;
/**
* This method is like `_.intersection` except that it accepts `iteratee`
* which is invoked for each element of each `arrays` to generate the criterion
* by which they're compared. The order and references of result values are
* determined by the first array. The iteratee is invoked with one argument:
* (value).
*
* @static
* @memberOf _
* @since 4.0.0
* @category Array
* @param {...Array} [arrays] The arrays to inspect.
* @param {Function} [iteratee=_.identity] The iteratee invoked per element.
* @returns {Array} Returns the new array of intersecting values.
* @example
*
* _.intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor);
* // => [2.1]
*
* // The `_.property` iteratee shorthand.
* _.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
* // => [{ 'x': 1 }]
*/
var intersectionBy = baseRest(function(arrays) {
var iteratee = last(arrays),
mapped = arrayMap(arrays, castArrayLikeObject);
if (iteratee === last(mapped)) {
iteratee = undefined;
} else {
mapped.pop();
}
return (mapped.length && mapped[0] === arrays[0])
? baseIntersection(mapped, baseIteratee(iteratee, 2))
: [];
});
return intersectionBy;
});