With the arrival of ES6 with sets and splat operator (at the time of being works only in Firefox, check compatibility table), you can write the following cryptic one liner:
var a = [34, 35, 45, 48, 49];
var b = [48, 55];
var union = [...new Set([...a, ...b])];
console.log(union);
Little explanation about this line: [...a, ...b]
concatenates two arrays, you can use a.concat(b)
as well. new Set()
create a set out of it and thus your union. And the last [...x]
converts it back to an array.