bbo/union_by.js

bbo is a utility library of zero dependencies for javascript.

'use strict';

var _rollupPluginBabelHelpers = require('./internal/_rollupPluginBabelHelpers.js');

/**
 * Returns every element that exists in any of the two arrays once,
 * after applying the provided function to each array element of both.
 */
var unionBy = (a, b, fn) => {
  var s = new Set(a.map(fn));
  return Array.from(new Set([].concat(_rollupPluginBabelHelpers._toConsumableArray(a), _rollupPluginBabelHelpers._toConsumableArray(b.filter(x => !s.has(fn(x)))))));
};

module.exports = unionBy;