备忘录flatten

Posted 2020-07-20 xiaoroad

function flatten(arr) {
  if(!Array.isArray(arr)) {
    return [arr];
  }

  var array = [];
  for(var i = 0; i < arr.length; i++) {
    array = array.concat(flatten(arr[i]));
  }
  return array;
}

flatten([1,[2,[3]],[4]]); // => [1,2,3,4]