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前言
树结构的数据操作对于一个开发者来说是一个必备的技能。在理论的业务开发中，咱们也会遇到许多树结构的体现，比方最常见的地区树，以及企业构造树、校级组织树等等。
上面整顿了一系列的对于 JavaScript 树的操作方法，联合示例，，置信大家在理论开发工作中或多或少都会用到。
数组扁平化
示例
const arr = [1, [2, [3, 4]], 5, [6]];办法
1、递归
const flatten = (arr) => {let res = [];
arr.map(item => {if(Array.isArray(item)) {res = res.concat(flatten(item));
} else {res.push(item);
}
});
return res;
}2、reduce
const flatten = (arr) => {return arr.reduce((result, item)=> {return result.concat(Array.isArray(item) ? flatten(item) : item);
}, []);
}3、flat
const flatten = (arr) => {return arr.flat(Infinity)
}运行后果
const result = flatten(arr);
console.log(result);
// 运行后果
[1, 2, 3, 4, 5, 6]数组转树形构造
示例
const arr = [
{
name: '小明',
id: 1,
pid: 0,
},
{
name: '小花',
id: 11,
pid: 1,
},
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
},
{
name: '小红',
id: 12,
pid: 1,
},
{
name: '小王',
id: 2,
pid: 0,
},
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]办法
1、非递归
const arrayToTree = (arr) => {let result = [];
if (!Array.isArray(arr) || arr.length === 0) {return result}
let map = {};
arr.forEach(item => map[item.id] = item);
arr.forEach(item => {const parent = map[item.pid];
if(parent){(parent.children || (parent.children=[])).push(item);
} else {result.push(item);
}
})
return result
}2、递归
const arrayToTree = (arr, pid) => {let res = [];
arr.forEach(item => {if(item.pid === pid){let itemChildren = arrayToTree(arr,item.id);
if(itemChildren.length) {item.children = itemChildren;}
res.push(item);
}
});
return res;
}运行后果
// const result = arrayToTree(arr);
const result = arrayToTree(arr, 0);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0,
"children": [
{
"name": "小花",
"id": 11,
"pid": 1,
"children": [
{
"name": "小华",
"id": 111,
"pid": 11
},
{
"name": "小李",
"id": 112,
"pid": 11
}
]
},
{
"name": "小红",
"id": 12,
"pid": 1
}
]
},
{
"name": "小王",
"id": 2,
"pid": 0,
"children": [
{
"name": "小林",
"id": 21,
"pid": 2
},
{
"name": "小李",
"id": 22,
"pid": 2
}
]
}
]树形构造转数组（扁平化）
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
children: [
{
name: '小花',
id: 11,
pid: 1,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
}
]
},
{
name: '小红',
id: 12,
pid: 1,
}
]
},
{
name: '小王',
id: 2,
pid: 0,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]
}
]办法
1、深度优先遍历
const treeToArray = (tree) => {
let stack = tree,
result = [];
while(stack.length !== 0){let pop = stack.pop();
result.push({
id: pop.id,
name: pop.name,
pid: pop.pid
})
let children = pop.children
if(children){for(let i = children.length-1; i >=0; i--){stack.push(children[i])
}
}
}
return result
}2、广度优先遍历
const treeToArray = (tree) => {
let queue = tree,
result = [];
while(queue.length !== 0){let shift = queue.shift();
result.push({
id: shift.id,
name: shift.name,
pid: shift.pid
})
let children = shift.children
if(children){for(let i = 0; i < children.length; i++){queue.push(children[i])
}
}
}
return result
}3、不必思考除 children 外的其余属性
const treeToArray = (source)=>{let res = []
source.forEach(item=>{res.push(item)
item.children && res.push(...treeToArray(item.children))
})
return res.map((item) => {if (item.children) {delete item.children}
return item
})
}运行后果
const result = treeToArray(tree);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0
},
{
"name": "小花",
"id": 11,
"pid": 1
},
{
"name": "小华",
"id": 111,
"pid": 11
},
{
"name": "小李",
"id": 112,
"pid": 11
},
{
"name": "小红",
"id": 12,
"pid": 1
},
{
"name": "小王",
"id": 2,
"pid": 0
},
{
"name": "小林",
"id": 21,
"pid": 2
},
{
"name": "小李",
"id": 22,
"pid": 2
}
]树筛选，保留符合条件的数据并返回树结构
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
show: true,
children: [
{
name: '小花',
id: 11,
pid: 1,
show: true,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
show: true,
}
]
},
{
name: '小红',
id: 12,
pid: 1,
}
]
},
{
name: '小王',
id: 2,
pid: 0,
show: true,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]
}
]办法
筛选出 show 为 true 数据
const filterTreeByFunc = (tree, func) => {if (!Array.isArray(tree) || tree.length === 0) {return []
}
return tree.filter(item => {item.children = item.children && filterTreeByFunc(item.children, func)
return func(item) || (item.children && item.children.length)
})
}
const func = (item) => {return item.show === true}运行后果
const result = filterTreeByFunc(tree, func);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0,
"show": true,
"children": [
{
"name": "小花",
"id": 11,
"pid": 1,
"show": true,
"children": [
{
"name": "小李",
"id": 112,
"pid": 11,
"show": true
}
]
}
]
},
{
"name": "小王",
"id": 2,
"pid": 0,
"show": true,
"children": []}
]查找某一节点在树中门路
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
children: [
{
name: '小花',
id: 11,
pid: 1,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
}
]
},
{
name: '小红',
id: 12,
pid: 1,
}
]
},
{
name: '小王',
id: 2,
pid: 0,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]
}
]办法
const getNodePath = (tree, id) => {if (!Array.isArray(tree) || tree.length === 0) {return []
}
const path = []
const treeFindPath = (tree, id, path) => {for (const item of tree) {path.push(item.id);
if (item.id === id) {return path}
if (item.children) {const findChildren = treeFindPath(item.children,id, path);
if (findChildren.length) {return findChildren;}
}
path.pop();}
return [];}
return treeFindPath(tree, id, path)
}运行后果
const result = getNodePath(tree, 112);
console.log(result);
// 运行后果
[1, 11, 112]含糊查问树
示例
const tree = [
{
name: '小明前端专家',
id: 1,
pid: 0,
children: [
{
name: '小花前端程序媛',
id: 11,
pid: 1,
children: [
{
name: '小华划水运动员',
id: 111,
pid: 11,
},
{
name: '小李摸鱼运动员',
id: 112,
pid: 11,
}
]
},
{
name: '小红摸鱼程序员',
id: 12,
pid: 1,
}
]
},
{
name: '小王内卷王',
id: 2,
pid: 0,
children: [
{
name: '小林摸鱼王',
id: 21,
pid: 2,
},
{
name: '小李后端程序员',
id: 22,
pid: 2,
}
]
}
]办法
const fuzzyQueryTree = (arr, value) => {if (!Array.isArray(arr) || arr.length === 0) {return []
}
let result = [];
arr.forEach(item => {if (item.name.indexOf(value) > -1) {const children = fuzzyQueryTree(item.children, value);
const obj = {...item, children}
result.push(obj);
} else {if (item.children && item.children.length > 0) {const children = fuzzyQueryTree(item.children, value);
const obj = {...item, children}
if (children && children.length > 0) {result.push(obj);
}
}
}
});
return result;
};运行后果
const result = fuzzyQueryTree(tree,'程序');
console.log(result);
// 运行后果
[
{
"name": "小明前端专家",
"id": 1,
"pid": 0,
"children": [
{
"name": "小花前端程序媛",
"id": 11,
"pid": 1,
"children": []},
{
"name": "小红摸鱼程序员",
"id": 12,
"pid": 1,
"children": []}
]
},
{
"name": "小王内卷王",
"id": 2,
"pid": 0,
"children": [
{
"name": "小李后端程序员",
"id": 22,
"pid": 2,
"children": []}
]
}
]树节点增加属性
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
children: [
{
name: '小花',
id: 11,
pid: 1,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
}
]
},
{
name: '小红',
id: 12,
pid: 1,
}
]
},
{
name: '小王',
id: 2,
pid: 0,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]
}
]办法
const addAttrToNodes = (tree) => {tree.forEach((item) => {
item.title = '新生代农民工'
if (item.children && item.children.length > 0) {addAttrToNodes(item.children)
}
})
return tree
}运行后果
const result = addAttrToNodes(tree);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0,
"children": [
{
"name": "小花",
"id": 11,
"pid": 1,
"children": [
{
"name": "小华",
"id": 111,
"pid": 11,
"title": "新生代农民工"
},
{
"name": "小李",
"id": 112,
"pid": 11,
"title": "新生代农民工"
}
],
"title": "新生代农民工"
},
{
"name": "小红",
"id": 12,
"pid": 1,
"title": "新生代农民工"
}
],
"title": "新生代农民工"
},
{
"name": "小王",
"id": 2,
"pid": 0,
"children": [
{
"name": "小林",
"id": 21,
"pid": 2,
"title": "新生代农民工"
},
{
"name": "小李",
"id": 22,
"pid": 2,
"title": "新生代农民工"
}
],
"title": "新生代农民工"
}
]树节点删除属性
示例
这里间接应用下面——树形构造节点增加属性 的运行后果
办法
const removeAttrFromNode = (tree) => {tree.forEach((item) => {
delete item.title
if (item.children && item.children.length > 0) {removeAttrFromNode(item.children)
}
})
return tree
}运行后果
const result = removeAttrFromNode(tree);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0,
"children": [
{
"name": "小花",
"id": 11,
"pid": 1,
"children": [
{
"name": "小华",
"id": 111,
"pid": 11
},
{
"name": "小李",
"id": 112,
"pid": 11
}
]
},
{
"name": "小红",
"id": 12,
"pid": 1
}
]
},
{
"name": "小王",
"id": 2,
"pid": 0,
"children": [
{
"name": "小林",
"id": 21,
"pid": 2
},
{
"name": "小李",
"id": 22,
"pid": 2
}
]
}
]删除树中的空 children
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
children: [
{
name: '小花',
id: 11,
pid: 1,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
children: []}
]
},
{
name: '小红',
id: 12,
pid: 1,
children: []}
]
},
{
name: '小王',
id: 2,
pid: 0,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
children: []}
]
}
]办法
const removeEmptyChildren = (tree) => {tree.forEach((item) => {if (item.children && item.children.length ===0) {delete item.children} else if (item.children && item.children.length > 0) {removeEmptyChildren(item.children)
}
})
return tree
}运行后果
const result = removeEmptyChildren(tree);
console.log(result);
// 运行后果
[
{
"name": "小明",
"id": 1,
"pid": 0,
"children": [
{
"name": "小花",
"id": 11,
"pid": 1,
"children": [
{
"name": "小华",
"id": 111,
"pid": 11
},
{
"name": "小李",
"id": 112,
"pid": 11
}
]
},
{
"name": "小红",
"id": 12,
"pid": 1
}
]
},
{
"name": "小王",
"id": 2,
"pid": 0,
"children": [
{
"name": "小林",
"id": 21,
"pid": 2
},
{
"name": "小李",
"id": 22,
"pid": 2
}
]
}
]获取树中所有的叶子节点
示例
const tree = [
{
name: '小明',
id: 1,
pid: 0,
children: [
{
name: '小花',
id: 11,
pid: 1,
children: [
{
name: '小华',
id: 111,
pid: 11,
},
{
name: '小李',
id: 112,
pid: 11,
}
]
},
{
name: '小红',
id: 12,
pid: 1,
}
]
},
{
name: '小王',
id: 2,
pid: 0,
children: [
{
name: '小林',
id: 21,
pid: 2,
},
{
name: '小李',
id: 22,
pid: 2,
}
]
}
]办法
const getAllLeaf = (tree) => {const result = []
const getLeaf = (tree) => {tree.forEach((item) => {if (!item.children) {result.push(item)
} else {getLeaf(item.children)
}
})
}
getLeaf(tree)
return result
}运行后果
const result = getAllLeaf(tree);
console.log(result);
// 运行后果
[
{
"name": "小华",
"id": 111,
"pid": 11
},
{
"name": "小李",
"id": 112,
"pid": 11
},
{
"name": "小红",
"id": 12,
"pid": 1
},
{
"name": "小林",
"id": 21,
"pid": 2
},
{
"name": "小李",
"id": 22,
"pid": 2
}
]参考
https://wintc.top/article/20
https://www.cnblogs.com/mengf…
https://blog.csdn.net/susuzhe…
https://blog.csdn.net/web_yue…
最初
本文整顿了一系列的对于 JavaScript 树的操作方法，相当于平时的一个总结。大家能够拿来即用，或者依据理论的业务进行参考批改。
如果大家有更好的实现形式，或者本人在开发中遇到的，然而下面没有波及到的，欢送提出来，大家一起探讨一起提高~
正文完
