DepthTraversal.js

gistfile1.txt

const preorderTraverse = (node) => {
  if(!node){
    return [];
  }
  return [node.value, ...preorderTraverse(node.left), ...preorderTraverse(node.right)];
};

const inorderTraverse = (node) => {
  if(!node){
    return [];
  }
  return [...inorderTraverse(node.left), node.value, ...inorderTraverse(node.right)]
};

const postorderTraverse = (node) => {
  if(!node){
    return [];
  }
  return [...postorderTraverse(node.left), ...postorderTraverse(node.right), node.value]
};


/*
describe('tests', function() {
  
  const tree = {
    value: 8,
    left: {
      value: 4,
      left: {
        value: 3,
        left: {
          value: 2,
          left: null,
          right: null
        },
        right: null
      },
      right: {
        value: 5,
        left: null,
        right: {
          value: 7,
          left: {
            value: 6,
            left: null,
            right: null
          }
        }
      }
    },
    right: {
      value: 12,
      left: {
        value: 10,
        left: {
          value: 9,
          left: null,
          right: null
        },
        right: {
          value: 11,
          left: null,
          right: null
        }
      }
    }
  };
  
  it('preorderTraverse', () => {
    expect(preorderTraverse(tree, [])).toEqual([8, 4, 3, 2, 5, 7, 6, 12, 10, 9, 11]);
  });
  
  it('inorderTraverse', () => {
    expect(inorderTraverse(tree, [])).toEqual([2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]);
  });
  
  it('postorderTraverse', () => {
    expect(postorderTraverse(tree, [])).toEqual([2, 3, 6, 7, 5, 4, 9, 11, 10, 12, 8]);
  });
});
*/