Create an array of unique values, in order, from the input arrays
$ npm install array-union
const arrayUnion = require('array-union');
arrayUnion([1, 1, 2, 3], [2, 3]);
//=> [1, 2, 3]
arrayUnion(['foo', 'foo', 'bar']);
//=> ['foo', 'bar']
arrayUnion(['馃惐', '馃', '馃惢'], ['馃', '馃寛']);
//=> ['馃惐', '馃', '馃惢', '馃寛']
arrayUnion(['馃惐', '馃'], ['馃惢', '馃'], ['馃惗', '馃寛', '馃寛']);
//=> ['馃惐', '馃', '馃惢', '馃惗', '馃寛']MIT 漏 Sindre Sorhus