1、深度遍历

let bt = {
    val: 'a',
    children: [
        {
            val: 'b',
            children: [
                {
                    val: 'd',
                    children: []
                },
                {
                    val: 'e',
                    children: []
                }
            ]
        },
        {
            val: 'c',
            children: [
                {
                    val: 'f',
                    children: []
                },
                {
                    val: 'g',
                    children: []
                }
            ]
        }
    ]
}

const dfs = root => {
    console.log(root.val)
    root.children.forEach(dfs)
}

dfs(bt)  

2、广度遍历

let tree = {
    val: 'a',
    children: [
        {
            val: 'b',
            children: [
                {
                    val: 'd',
                    children: []
                },
                {
                    val: 'e',
                    children: []
                }
            ]
        },
        {
            val: 'c',
            children: [
                {
                    val: 'f',
                    children: []
                },
                {
                    val: 'g',
                    children: []
                }
            ]
        }
    ]
}

const bfs = root => {
    let q = [root] 
    while(q.length > 0) {
        let n = q.shift()
        console.log(n.val)
        n.children.forEach(child => q.push(child))

    }
}

bfs(tree)