## 扁平化 ``` var arr = [1,2, [3,4], [5,6, [7, 8]]] const newArr = function(arr) { return arr.reduce((prev, cur) => { return Array.isArray(cur) ? prev.concat(newArr(cur)) : prev.concat(cur) }, []) } newArr(arr) ``` ## 扁平化并去重 ``` const wrap = function (arr) { return arr.reduce((prev, cur) => { return Array.isArray(cur) ? prev.concat(newArr(cur)) : prev.concat(cur) }, []) } const arr1 = [...new Set(wrap(arr))] console.log(arr1) ```