整理了一系列的JavaScript树操作方法，不用再一遍又一遍的百度了

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。在实际的业务开发中，我们也会遇到许多树结构的体现，比如最常见的地域树，以及企业结构树、校级组织树等等。

下面整理了一系列的关于JavaScript树的操作方法，结合示例，相信大家在实际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]];

方法

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)
}

运行结果

const result = flatten(arr);
console.log(result);// 运行结果
[1, 2, 3, 4, 5, 6]

数组转树形结构

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,}
]

方法

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;
}

运行结果

// const result = arrayToTree(arr);
const result = arrayToTree(arr, 0);
console.log(result);// 运行结果
[{"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}]}
]

树形结构转数组（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,}]}
]

方法

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.childrenif(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.childrenif(children){for(let i = 0; i < children.length; i++){queue.push(children[i])}}}return result
}

3、不用考虑除children外的其他属性

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})
}

运行结果

const result = treeToArray(tree);
console.log(result);// 运行结果
[{"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,}]}
]

方法

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
}

运行结果

const result = filterTreeByFunc(tree, func);
console.log(result);// 运行结果
[{"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路径

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,}]}
]

方法

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)
}

运行结果

const result = getNodePath(tree, 112);
console.log(result);// 运行结果
[1, 11, 112]

模糊查询树

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,}]}
]

方法

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;
};

运行结果

const result = fuzzyQueryTree(tree,'程序');
console.log(result);// 运行结果
[{"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": []}]}
]

树节点添加属性

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,}]}
]

方法

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
}

运行结果

const result = addAttrToNodes(tree);
console.log(result);// 运行结果
[{"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

这里直接使用上面——树形结构节点添加属性的运行结果

方法

const removeAttrFromNode = (tree) => {tree.forEach((item) => {delete item.titleif (item.children && item.children.length > 0) {removeAttrFromNode(item.children)}})return tree
}

运行结果

const result = removeAttrFromNode(tree);
console.log(result);// 运行结果
[{"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: []}]}
]

方法

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
}

运行结果

const result = removeEmptyChildren(tree);
console.log(result);// 运行结果
[{"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,}]}
]

方法

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
}

运行结果

const result = getAllLeaf(tree);
console.log(result);// 运行结果
[{"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/mengff/p/13142128.html

https://blog.csdn.net/susuzhe123/article/details/95353403

https://blog.csdn.net/web_yueqiang/article/details/89483971

最后

本文整理了一系列的关于JavaScript树的操作方法，相当于平时的一个总结。大家可以拿来即用，或者根据实际的业务进行参考修改。

如果大家有更好的实现方式，或者自己在开发中遇到的，但是上面没有涉及到的，欢迎提出来，大家一起讨论一起进步~