JS construct binary tree

The way 1：

class Node {
     //  Define the node 
	constructor(data){
    
		this.data = data
	    this.leftChild = null
	    this.rightChild = null
    }
}

const createTree = (arr) => {
     //  Create a binary tree 
	let tree = new Node(arr[0])
	let Nodes = [tree]
	let i = 1
    for (let node of Nodes){
    
		Nodes.push(node.leftChild = new Node (arr[i]))
        i += 1
        if (i == arr.length) return tree
        Nodes.push(node.rightChild = new Node(arr[i]))
        i += 1
        if (i == arr.length) return tree
	}
}
let datas = ['A','B','C','D','E','F','G',null,'H']
let t = createTree(datas)

The way 2：

function TreeNode(val, left, right) {
    
	this.val = (val===undefined ? 0 : val)
    this.left = (left===undefined ? null : left)
    this.right = (right===undefined ? null : right)
}
let biTree = new TreeNode(3);
biTree.left = new TreeNode(5);
biTree.right = new TreeNode(1);
biTree.left.left = new TreeNode(6);
biTree.left.right = new TreeNode(2);
biTree.left.right.left = new TreeNode(7);
biTree.left.right.right = new TreeNode(4);
biTree.right.left = new TreeNode(0);
biTree.right.right = new TreeNode(8);

The way 3：

const bt = {
    
    val: 1,
    left: {
    
        val: 2,
        left: {
    
            val: 4,
            left: null,
            right: null,
        },
        right: {
    
            val: 5,
            left: {
    
                val: 8,
                left: null,
                right: null,
            },
            right: {
    
                val: 9,
                left: null,
                right: null,
            },
        },
    },
    right: {
    
        val: 3,
        left: {
    
            val: 6,
            left: null,
            right: null,
        },
        right: {
    
            val: 7,
            left: null,
            right: null,
        },
    },
};