joinpursuit/pursuit-core-web-express-routing-lab

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" }
}