扁平化数组

export function flatArr(arr，childKey) {
if (!Array.isArray(arr)) {
return []
}
let newArr = [];
arr.forEach(item => {
let oo = {};
for (let key in item) {
if (key !== childKey) {
oo[key] = item[key]
}
}
newArr.push(oo);
if (item[childKey]) {
newArr = newArr.concat(flatArr(item.son,childKey))
}
})
return newArr;
}