Converter Quiz

Introduction

Implement a command-line Node.js application named convert.js that can convert lengths and weights. You can check if your code is correct by running the unit tests in converter.spec.js.

1. Everybody has to do his/her best to come up with a solution.

2. Have the chance to earn one point for your grade by delivering a solution that passes all unit tests.

3. Have the chance to earn one point - and my respect ;-) - if you manage to implement the entire program in less than 10 lines of code. It is possible.

Specification

convert.js receives exactly four parameters:

1. A float value that should be converted (e.g. 5).
2. A source unit (e.g. m = meters).
3. The constant string to.
4. A target unit (e.g. cm = centimeters).

Therefore, a typical call looks like this node convert.js 5 m to cm.

convert.js must print its result to stdout. The result of the previous example should be: 5 m are 500 cm. If wrong parameters were specified, the result on stdout should be: Invalid parameters.

The converter must be able to convert

1. the length units m (meters), cm (centimeters) and mm (millimeters).
2. the weight units kg (kilograms) and g (grams).

Each length unit can be converted into each other length unit including itself (e.g. 5 m to m results in 5 m are 5 m). Each weight unit can be converted into each other weight unit including itself. Length units cannot be converted into weight units and vice versa (must result in Invalid parameters).

Hints

To run the unit tests and check your solution, execute the following steps:

1. Open a command line/terminal window and navigate to the root directory of this quiz.

2. Run npm install to get the NPM packages necessary for running the tests.

3. Whenever you want to run the unit tests, execute npm run test. The result will be something like this:

Extra Challenge

Do you want an extra challenge that is quite hard? Here you are: If the user specifies units that you do not know (e.g. 3.1415 rad to deg), you can call WolframAlpha's web API.

• Read more about programming with WolframAlpha...
• Create a developer account with the free plan
• Create a demo app
• Try a query interactively with a Web API client like Insomnia or Postman: http://api.wolframalpha.com/v2/query?input=5%20inch%20to%20m&appid=...
• Use a package (e.g. node-fetch) to do the Web API query in your application

Note that this challenge is only for students who want to invest a significant amount of time in this exercise. It is not mandatory!