var a = [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5], b = [11,22,33,44,55]; a.reduce((acc,ele,idx) => ((idx + 1) % 3 ? acc.push(ele) : acc.push(ele, b.shift()), acc), []);

优雅么。。。

export function join(first: T[], second: T[], firstSize: number, secondSize: number): T[] { let out: T[] = [] let i = 0 for (; firstSize * i < first.length && secondSize * i < second.length; i++) { out = out.concat( first.slice(firstSize * i, firstSize), second.slice(secondSize * i, secondSize), ) } out = out.concat(first.slice(firstSize * i), second.slice(secondSize * i)) return out }