How to make binary tree from array in javascript?

Question

I have an array var array = [8,10,12,5,3,6];

Logic

1. First node would be root node.
2. If new node value is less or equal =< than parent node, It would be left node of parent node
3. If new node value is greater > than parent node, It would be right node of parent node

And I am trying to achieve output like below object:

{
   value:8,
   left:{
      value:5,
      left:{ value:3 },
      right:{value:6}
   },
   right:{
      value:10,
      right:{value:12}
   }
}

Which would be in image like this

I tried below code:

var arr = [8,10,12,5,3,6];
var root = arr[0];
var rv = {};
for (var i = 0; i < arr.length; i++){
    if(arr[i] < root){
    rv.left = arr[i];
  }else{
    rv.right = arr[i];
  }
}
console.log(rv);

Please help me to solve this.

Answer 1

You could use a Node instance for new nodes and a function for inserting nodes.

Then iterate the values and build a new tree.

function Node(value) {
    this.value = value;
    // this.left = null;
    // this.right = null;
}

function insertNode(tree, value) {
    var node = tree,
        key;
    while (node.value !== value) {
         key = value < node.value ? 'left' : 'right';
         if (!node[key]) {
             node[key] = new Node(value);
             break;
         }
         node = node[key];
    }
    return tree;
}

var array = [8, 10, 12, 5, 3, 6],
    tree = array.reduce((t, v) => t ? insertNode(t, v) : new Node(v), null);

console.log(tree);

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