intersectionBy.js (1467B)
1 var arrayMap = require('./_arrayMap'), 2 baseIntersection = require('./_baseIntersection'), 3 baseIteratee = require('./_baseIteratee'), 4 baseRest = require('./_baseRest'), 5 castArrayLikeObject = require('./_castArrayLikeObject'), 6 last = require('./last'); 7 8 /** 9 * This method is like `_.intersection` except that it accepts `iteratee` 10 * which is invoked for each element of each `arrays` to generate the criterion 11 * by which they're compared. The order and references of result values are 12 * determined by the first array. The iteratee is invoked with one argument: 13 * (value). 14 * 15 * @static 16 * @memberOf _ 17 * @since 4.0.0 18 * @category Array 19 * @param {...Array} [arrays] The arrays to inspect. 20 * @param {Function} [iteratee=_.identity] The iteratee invoked per element. 21 * @returns {Array} Returns the new array of intersecting values. 22 * @example 23 * 24 * _.intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); 25 * // => [2.1] 26 * 27 * // The `_.property` iteratee shorthand. 28 * _.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x'); 29 * // => [{ 'x': 1 }] 30 */ 31 var intersectionBy = baseRest(function(arrays) { 32 var iteratee = last(arrays), 33 mapped = arrayMap(arrays, castArrayLikeObject); 34 35 if (iteratee === last(mapped)) { 36 iteratee = undefined; 37 } else { 38 mapped.pop(); 39 } 40 return (mapped.length && mapped[0] === arrays[0]) 41 ? baseIntersection(mapped, baseIteratee(iteratee, 2)) 42 : []; 43 }); 44 45 module.exports = intersectionBy;