JavaScript之递归遍历数组集合

数据例子：

let ary = [{name: '1', child: [{id: 1, label: '1'}, {id: 2, label: '2'}]}, {name: '2', child: [{id: 3, label: '3'}, {id: 4, label: '4'}]}]

递归方法：

var flatten = (arr, prev = {}) => {
  return arr.reduce((pre, cur, idx) => {
    let obj = idx == 0 && prev.child ? {rowSpan: prev.child.length} : {rowSpan： 0};
    return pre.concat(Array.isArray(cur.child) ? flatten(cur.child, cur) : {...cur, name: prev.name, ...obj})
  }, [])
}

最后调用：

var new_arr = flatten(ary);
console.log(new_arr);  // [{id: 1, label: "1", name: "1", rowSpan: 2}, {id: 2, label: "2", name: "1", rowSpan: 0}, {id: 3, label: "3", name: "2", rowSpan: 2}, {id: 4, label: "4", name: "2", rowSpan: 0}]