3 module.exports = function union(init) {
4 if (!Array.isArray(init)) {
5 throw new TypeError('arr-union expects the first argument to be an array.');
8 var len = arguments.length;
12 var arg = arguments[i];
15 if (!Array.isArray(arg)) {
19 for (var j = 0; j < arg.length; j++) {
22 if (init.indexOf(ele) >= 0) {