​day024: JS中flat---数组扁平化

let ary = [1, [2, [3, [4, 5]]], 6];// -> [1, 2, 3, 4, 5, 6]
let str = JSON.stringify(ary);

ary = arr.flat(Infinity);

ary = str.replace(/(\[|\])/g, '').split(',')

str = str.replace(/(\[|\]))/g, '');
str = '[' + str + ']';
ary = JSON.parse(str);

let result = [];
let fn = function(ary) {
  for(let i = 0; i < ary.length; i++) {
    let item = ary[i];
    if (Array.isArray(ary[i])){
      fn(item);
    } else {
      result.push(item);
    }
  }
}

function flatten(ary) {
    return ary.reduce((pre, cur) => {
        return pre.concat(Array.isArray(cur) ? flatten(cur) : cur);
    }, []);
}
let ary = [1, 2, [3, 4], [5, [6, 7]]]
console.log(flatten(ary))

//只要有一个元素有数组，那么循环继续
while (ary.some(Array.isArray())) {
  ary = [].concat(...ary);
}