Tree Traversal Level Order BFS in DSA Javascript - Build from Scratch

Tree Traversal Level Order BFS

📖 Scenario: You are working with a simple family tree. Each person has a name and may have children. You want to visit each family member level by level, starting from the oldest ancestor.

🎯 Goal: Build a program that performs a level order traversal (Breadth-First Search) on a tree structure and prints the names of family members level by level.

📋 What You'll Learn

Create a tree structure using JavaScript objects with name and children properties

Use a queue to help with level order traversal

Traverse the tree level by level and collect names in order

Print the names in the order they are visited

💡 Why This Matters

🌍 Real World

Level order traversal is used in many real-world applications like finding shortest paths in networks, organizing hierarchical data, and scheduling tasks.

💼 Career

Understanding tree traversals is important for software developers working with data structures, databases, and algorithms in interviews and real projects.

1

Create the family tree structure

Create a variable called familyTree that represents this tree:

- Root node with name "Grandpa"
- children array with two nodes:
- First child with name "Dad" and no children
- Second child with name "Uncle" and no children

DSA Javascript

// Create the familyTree object with the exact structure
// Your code here

Hint

Use nested objects with name and children properties. The children property is an array.

2

Create a queue for traversal

Create a variable called queue and set it to an array containing only the familyTree variable.

DSA Javascript

const familyTree = {
  name: "Grandpa",
  children: [
    { name: "Dad", children: [] },
    { name: "Uncle", children: [] }
  ]
};

// Create the queue array with familyTree inside
// Your code here

Hint

A queue can be an array where you add and remove elements from ends. Start with the root node inside.

3

Traverse the tree level by level

Create an empty array called result. Use a while loop that runs while queue.length is greater than 0. Inside the loop:
- Remove the first element from queue and call it current
- Add current.name to result
- Add all current.children to the end of queue using push(...current.children)

DSA Javascript

const familyTree = {
  name: "Grandpa",
  children: [
    { name: "Dad", children: [] },
    { name: "Uncle", children: [] }
  ]
};

const queue = [familyTree];

// Create an empty array result
// Use a while loop to traverse the tree
// Your code here

Hint

Use shift() to remove from front and push(...) to add children to the back of the queue.

4

Print the traversal result

Print the result array using console.log(result).

DSA Javascript

const familyTree = {
  name: "Grandpa",
  children: [
    { name: "Dad", children: [] },
    { name: "Uncle", children: [] }
  ]
};

const queue = [familyTree];
const result = [];

while (queue.length > 0) {
  const current = queue.shift();
  result.push(current.name);
  queue.push(...current.children);
}

// Print the result array
// Your code here

Hint

Use console.log(result) to see the names in level order.