intersection.js

"use strict";

var value    = require("../../object/valid-value")
  , contains = require("./contains")
  , byLength = require("./_compare-by-length")
  , filter   = Array.prototype.filter
  , push     = Array.prototype.push
  , slice    = Array.prototype.slice;

module.exports = function (/* …list*/) {
	var lists;
	if (!arguments.length) slice.call(this);
	push.apply(lists = [this], arguments);
	lists.forEach(value);
	lists.sort(byLength);
	return lists.reduce(function (list1, list2) {
		return filter.call(list1, function (item) {
			return contains.call(list2, item);
		});
	});
};