Modularizing Code

Module2.js

Question1 Write program to implement Doubly Linked List -> use module pattern and import in other file to perform operation

//doubly-linked_list.js 
function Node(value) {
    this.data = value;
    this.previous = null;
    this.next = null;
}
function DoublyList() {
    this._length = 0;
    this.head = null;
    this.tail = null;
}
DoublyList.prototype.add = function(value) {
    var node = new Node(value);
     if (this._length) {
        this.tail.next = node;
        node.previous = this.tail;
        this.tail = node;
    } else {
        this.head = node;
        this.tail = node;
    }
 
    this._length++;
    return node;
};
export default DoublyList

//add_module.js
import add from './doubly-linked_list.js' 
doublylist = new DoublyList
doublylist.add(1);
doublylist.add(2);
doublylist.add(3);
console.log(doublylist);


Question2 Write matrix program to find sum of elements using module pattern.
Solution
 //Matrix_module.js 

function get_sum(arr) { 
   var sum = 0;
  arr.forEach(function(v) {
      if (typeof v == 'object')
        sum += MatrixSum(v);
    else  
        sum += v
  })
  return sum; 
} 
export default get_sum

//consume_module.js

import get_sum from './MatrixModule.js' 
sum = get_sum([[1, 2, 3], [1, 2, 3], [1, 2, 3]]); 
console.log(sum);

Question3 Get data from rest api using npm modules.
Solution
const request = require('request');
const util = require('util');  

function getUserInfo(username) {  
        request({
            url: `https://api.stackexchange.com/2.2/tags/ruby/related?site=stackoverflow`,
            method: 'GET'
          }, function (err, response, body) {
        if (err) {
         console.error(err);
        }else{
         console.log(util.inspect(body, false, null))
        }

         });
};


Question4 Write a program to catch exceptions with your own examples. 
Solution 
 let num = 1;
try {
    num.toPrecision(500);
}
catch(err) {
    console.log(err.name);
};