Express-Routing-Lab

In this lab you will get to build a small server that can serve us as calculator for simple math operations.

1. Calculator API - Four Routes

Backend

In a file calculatorApi1.js, create and express server that works as a basic calculator API.

Create four routes/endpoints, /add, /sub, /mul, /div. Each of the routes will then accept two numbers as route parameters.

Here is what a route in your app would look like: /add/:num1/:num2
In each route, convert the numbers to integers using parseInt.
Respond to each request with an object that contains both numbers and the result.

For example, if the users navigates to http://localhost:8000/add/2/4, the response should be JSON like:

{"num1": 2, "num2": 4, "result": 6}
If either of the parameters is not a number, respond with an string like "numbers only".
If the user navigates to any other route, respond with an explanatory message about your API.

Frontend

Build a frontend where a user can interact with your calculator server. It should look something like this:

2. Calculator API - One Route

In a file calculatorApi2.js, convert your calculator API to take the operator as a route parameter as well. Now you will only need one route. If the operator is not valid, send an appropriate response like "the operator is not supported".

Hints

Since you will have only one route or endpoint what would that be?
This calculator server/API should work exactly the same as your previous for the basic operations. But you should see that your code is much shorter.
How could you make the operator portion of the URL be a parameter itself? So that it can be captured/seen in req.params

3. Challenge - Base Conversion API

Create an express server that converts numbers between three bases: decimal, binary, and hexadecimal.

To convert a decimal number to binary and hex:

let num = 10;
num.toString(2) // '1010'
num.toString(16) // 'a'

To convert binary and hex strings to decimal:

let hexStr = 'a'
parseInt(hexStr, 16) // 10
let binaryStr = '1010'
parseInt(binaryStr, 2) // 10

On every request, the server will expect a url of the following structure:

localhost:8000/{number}/{bin|dec|hex}

It will return an object that contains {number} and all conversions for {number} with the provided base.

If only a number is provided, e.g. localhost:8000/{number} - assume {number} has a decimal base and return an object with all conversions.

Example 1: on url localhost:8000/10 the server should return:

{
  "original": { "value":"10", "base":10 },
  "conversions": { "decimal":"10", "binary":"1010", "hex":"a" }
}

Example 2: on url localhost:8000/11/bin the server should return

{
  "original": { "value": "11", "base":2 },
  "conversions": { "decimal": "3", "binary": "11", "hex":" 3" }
}