Binary tree in JS (Breadth first search, insort, insert)

BinaryTree.js

/** recursively search in the tree where the current value can be inserted */
function find(value, node) {
	if(node.value === undefined || node.value === value) {
		return node;
	}
	if(node.value > value) {
		return find(value, node.left);
	}
	return find(value, node.right);
}

/** traverse the tree with insort method */
function inSort(node) {
	var value = [];
	if(node.left) {
		value = value.concat(inSort(node.left));
	}
	if(node.value !== undefined) {
		value = value.concat([node]);
	}
	if(node.right) {
		value = value.concat(inSort(node.right));
	}
	return value;
}

/* create a tree from an array of values */
function createTree(values, rootIndex) {
	var root = {
		left: {},
		right: {},
		value: values[rootIndex]
	};
	values.forEach(function(value) {
		var node = find(value, root);
		if(value === node.value) { return; }
		node.value = value;
		node.left = {};
		node.right = {};
	});
	return root;
}

/* breadth first search */
function BFS(tree) {
    var levels = [];
    function traverse(root, level) {
        level = level || 0;
        levels[level] = levels[level] || [];
        var nextLevel = level + 1;
        if(root.left) {
            traverse(root.left, nextLevel);
        }
        if(root.value) {
			if(!levels[level]) { debugger; }
            levels[level].push(root.value);
        }
        if(root.right) {
            traverse(root.right, nextLevel);
        }
        return levels;
    }
    return traverse(tree).join("\n");
}

//values to put in the tree
var values = [88,97,56,41,27,16,95,54,28];

//create tree
var tree = createTree(values, 0);
console.log('tree:', tree);

//insort tree traversing
var sorted = inSort(tree);
console.log('sorted:', sorted);

//recreate tree with median as starting point
var median = sorted[Math.round(sorted.length / 2)].value;
var treeMedian = createTree(values, values.indexOf(median));
console.log('tree median (', median, '):', treeMedian);

//Breadth first search
console.log(BFS(treeMedian));