如何通过数组JavaScript中的父键生成子键？
假设我们有一个这样的对象数组-
const arr = [
{ id: 1, parent_id: 0, title: 'Movies' },
{ id: 2, parent_id: 0, title: 'Music' },
{ id: 3, parent_id: 1, title: 'Russian movies' },
{ id: 4, parent_id: 2, title: 'Russian music' },
{ id: 5, parent_id: 3, title: 'New' },
{ id: 6, parent_id: 3, title: 'Top10' },
{ id: 7, parent_id: 4, title: 'New' },
{ id: 8, parent_id: 4, title: 'Top10' },
{ id: 9, parent_id: 0, title: 'Soft' }
];我们需要编写一个函数，该函数接受此数组并返回一个新的对象数组，每个对象都有一个额外的属性“child”，该属性必须是对象的所有id的数组，这些id是特定对象的直接或间接子对象。
因此，输出应类似于-
[
{ id: 1, parent_id: 0, title: 'Movies', childs: [ 3, 5, 6 ] },
{ id: 2, parent_id: 0, title: 'Music', childs: [ 4, 7, 8 ] },
{ id: 3, parent_id: 1, title: 'Russian movies', childs: [ 5, 6 ] },
{ id: 4, parent_id: 2, title: 'Russian music', childs: [ 7, 8 ] },
{ id: 5, parent_id: 3, title: 'New', childs: [] },
{ id: 6, parent_id: 3, title: 'Top10', childs: [] },
{ id: 7, parent_id: 4, title: 'New', childs: [] },
{ id: 8, parent_id: 4, title: 'Top10', childs: [] },
{ id: 9, parent_id: 0, title: 'Soft', childs: [] }
]现在，让我们编写此函数的代码-
示例
const arr = [
{ id: 1, parent_id: 0, title: 'Movies' },
{ id: 2, parent_id: 0, title: 'Music' },
{ id: 3, parent_id: 1, title: 'Russian movies' },
{ id: 4, parent_id: 2, title: 'Russian music' },
{ id: 5, parent_id: 3, title: 'New' },
{ id: 6, parent_id: 3, title: 'Top10' },
{ id: 7, parent_id: 4, title: 'New' },
{ id: 8, parent_id: 4, title: 'Top10' },
{ id: 9, parent_id: 0, title: 'Soft' }
];
const generateChild = arr => {
return arr.reduce((acc, val, ind, array) => {
const childs = [];
array.forEach((el, i) => {
if(childs.includes(el.parent_id) || el.parent_id === val.id){
childs.push(el.id);
};
});
return acc.concat({...val, childs});
}, []);
};
console.log(generateChild(arr));输出结果
控制台中的输出将为-
[
{ id: 1, parent_id: 0, title: 'Movies', childs: [ 3, 5, 6 ] },
{ id: 2, parent_id: 0, title: 'Music', childs: [ 4, 7, 8 ] },
{ id: 3, parent_id: 1, title: 'Russian movies', childs: [ 5, 6 ] },
{ id: 4, parent_id: 2, title: 'Russian music', childs: [ 7, 8 ] },
{ id: 5, parent_id: 3, title: 'New', childs: [] },
{ id: 6, parent_id: 3, title: 'Top10', childs: [] },
{ id: 7, parent_id: 4, title: 'New', childs: [] },
{ id: 8, parent_id: 4, title: 'Top10', childs: [] },
{ id: 9, parent_id: 0, title: 'Soft', childs: [] }
]