node.js

const Node = {
    value: null,
    parent: null,
    left: null,
    right: null,
    create: function(props={}) {
        let node = Object.create(this);
        Object.keys(this).forEach( (key)=> {
            node[key] = props[key] || this[key]
        })
        return node
    },
    add: function(node) {
        if (!this.value) { this.createRoot(node) }
        if (node.value < this.value) { this.addLeft(node) }
        else if (node.value > this.value) { this.addRight(node) }
    },
    createRoot: function(node) {
        this.value = node.value
    },
    addLeft: function(node) {
        if (this.left) {
            this.left.add(node)
        } else {
            this.left = node
        }
    },
    addRight: function(node) {
        if (this.right) {
            this.right.add(node)
        } else {
            this.right = node
        }
    },
}

let root = Node.create({value: 109})