js 数组扁平

// 数组扁平和去重
var arr = [[1,2,2],[3,4,5,5],[6,7,7,9,[11,12,[12,13,[14]]]],10];

function hello (arr) {
    let res = []
    for (let i = 0; i < arr.length;i++) {
        if (Array.isArray(arr[i])) {
            res = res.concat(hello(arr[i]))
        } else {
            res.push(arr[i])
        }
    }
    return [...new Set(res)]
}
hello(arr)