Set()合并问题

Question

对于ES6的Set类型有没有API可以直接合并两个Set()

Answer 1

const a = new Set( [ 1, 2 ] )

const b = new Set( [ 3, 4 ] )

// 合并ab

const c = new Set( [ ...a, ...b ] )    // [ 1, 2, 3, 4 ]