MWA Homework 02

Written Exercises

1. Explain why do we want sometimes to use setImmediate instead of using setTimeout?
2. Explain the difference between process.nextTick and setImmediate?
3. Name 10 core modules that Node provides by default, and 10 of the Global objects?

Exercise 02

Given the node application code within the exercise02 folder, install all the dependencies with npm i command, and run the application with npm run start command.

Note how the get_data() method within the data.ts file returns the following response body:

interface Todo { "userId": number, "id": number, "title": string, "completed": boolean }

const response_body = [
  { "userId": 1, "id": 1, "title": "delectus", "completed": false },
  { "userId": 1, "id": 2, "title": "quis officia", "completed": false },
  { "userId": 2, "id": 3, "title": "suscipit incidunt", "completed": false }
  // ...
]

Complete the code in format.ts and convert the response asynchronously into an object grouping the Todo items by userId, as follows:

const desired_response = {
    1 : [
      { "id": 1, "title": "delectus", "completed": false}, 
      { "id": 2, "title": "quis officia", "completed": false}
    ],
    2 : [
      { "id": 3, "title": "suscipit incidunt", "completed": false }
    ]
  // ...
}

The conversion allows for improving the time complexity of finding all Todo items for a specific user from O(n) to O(1).

Create a new markdown file solution02.md and explain in detail the performance implications of your solution on the node process.