1.分别用广度优先遍历和深度优先遍历展开下面节点

• 示例

var tree = {name: 'root',children: [{name: 'child1',children: [{name: 'child1_1',children: []}, { name: 'child1_2', children: [] }]}, {name: 'child2',children: [{name: 'child2_1',children: []}]}, {name: 'child3',children: [{name: 'child2_1',children: []}]}]
};
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广度优先遍历：

function wideTraversal(node) {var nodes = [];if (node != null) {var queue = [];queue.unshift(node);while (queue.length != 0) {var item = queue.shift();nodes.push(item.name);var children = item.children;for (var i = 0; i < children.length; i++) {queue.push(children[i]);}}}return nodes;
}
console.log(wideTraversal(tree))
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输出结果：

[ 'root','child1','child2','child3','child1_1','child1_2','child2_1','child2_1' ]

深度优先遍历：

function traverseTree(node) {var child = node.children,arr = [];arr.push(node.name);if (child) {child.forEach(function(node) {arr = arr.concat(traverseTree(node));});}return arr;
}
console.log(traverseTree(tree))
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输出结果：

[ 'root','child1','child1_1','child1_2','child2','child2_1','child3','child2_1' ]

2.关系型数组转换成树形结构对象

类似：

var data = [{ parentId: 0, id: 1, value: '1' },{ parentId: 3, id: 2, value: '2' },{ parentId: 0, id: 3, value: '3' },{ parentId: 1, id: 4, value: '4' },{ parentId: 1, id: 5, value: '5' }
]
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期望输出：

[
{id:1,value:'1',
children:[{id:4,value:'4',children:[]},
{id:5,value:'5',children:[]}]},
{id:3,value:'3',
children:[id:2,value:'2',children:[]]}]
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代码：

var getJsonTree = function(data, parentId) {var itemArr = [];for (var i = 0; i < data.length; i++) {var node = data[i];//data.splice(i, 1)if (node.parentId == parentId) {var newNode = { id: node.id, value: node.value, children: getJsonTree(data, node.id) };itemArr.push(newNode);}}return itemArr;
}
console.log(getJsonTree(data, 0))
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