Node.js — Extend Multiple Classes (Multi Inheritance)

Node.js benefits from new language features in JavaScript. The introduction of classes in JavaScript is a great step towards better extensibility.

You provide functionality in a base class, let other classes extend this base class, and use the given methods.

But how to extend multiple classes in Node.js? Read on to see how that works!

Node.js Series Overview

  1. String Replace All Appearances
  2. Remove All Whitespace From a String in JavaScript
  3. Generate a Random ID or String in Node.js or JavaScript
  4. Remove Extra Spaces From a String in JavaScript or Node.js
  5. Remove Numbers From a String in JavaScript or Node.js
  6. Get the Part Before a Character in a String in JavaScript or Node.js
  7. Get the Part After a Character in a String in JavaScript or Node.js
  8. How to Check if a Value is a String in JavaScript or Node.js
  9. Check If a String Includes All Strings in JavaScript/Node.js/TypeScript
  10. Check if a Value is a String in JavaScript and Node.js
  11. Limit and Truncate a String to a Given Length in JavaScript and Node.js
  12. Split a String into a List of Characters in JavaScript and Node.js
  13. How to Generage a UUID in Node.js
  14. Reverse a String in JavaScript or Node.js
  15. Split a String into a List of Lines in JavaScript or Node.js
  16. Split a String into a List of Words in JavaScript or Node.js
  17. Detect if a String is in camelCase Format in Javascript or Node.js
  18. Check If a String Is in Lowercase in JavaScript or Node.js
  19. Check If a String is in Uppercase in JavaScript or Node.js
  20. Get the Part After First Occurrence in a String in JavaScript or Node.js
  21. Get the Part Before First Occurrence in a String in JavaScript or Node.js
  22. Get the Part Before Last Occurrence in a String in JavaScript or Node.js
  23. Get the Part After Last Occurrence in a String in JavaScript or Node.js
  24. How to Count Words in a File
  25. How to Shuffle the Characters of a String in JavaScript or Node.js
  26. Append Characters or Words to a String in JavaScript or Node.js (Coming soon)
  27. Check if a String is Empty in JavaScript or Node.js (Coming soon)
  28. Ensure a String Ends with a Given Character in JavaScript or Node.js (Coming soon)
  29. Left-Trim Characters Off a String in JavaScript or Node.js (Coming soon)
  30. Right-Trim Characters Off a String in JavaScript or Node.js (Coming soon)
  31. Lowercase the First Character of a String in JavaScript or Node.js (Coming soon)
  32. Uppercase the First Character of a String in JavaScript or Node.js (Coming soon)
  33. Prepend Characters or Words to a String in JavaScript or Node.js (Coming soon)
  1. Get Number of Seconds Since Epoch in JavaScript
  2. Get Tomorrow’s Date in JavaScript
  3. Increase a Date in JavaScript by One Week
  4. Add Seconds to a Date in Node.js and JavaScript
  5. Add Month(s) to a Date in JavaScript or Node.js
  6. Add Week(s) to a Date in JavaScript or Node.js
  7. Get the Current Year in JavaScript or Node.js
  8. How to Get a UNIX Timestamp in JavaScript or Node.js
  9. How to Convert a UNIX Timestamp to a Date in JavaScript or Node.js
  10. Add Days to a Date in JavaScript or Node.js
  11. Get Yesterday's Date in JavaScript or Node.js
  12. Add Minutes to a Date in JavaScript or Node.js (Coming soon)
  13. Add Hours to a Date in JavaScript or Node.js (Coming soon)
  14. Check If a Date Is Today in JavaScript or Node.js (Coming soon)
  15. Check If a Date is Tomorrow in JavaScript or Node.js (Coming soon)
  16. Check If a Date is Yesterday in JavaScript or Node.js (Coming soon)
  17. How to Format a Date YYYY-MM-DD in JavaScript or Node.js (Coming soon)

Install the “extends-classes” Package

By default, each class in Node.js can extend only a single class. That means, to inherit from multiple classes, you’d need to create a hierarchy of classes that extend each other.

But wait, there’s a simpler solution. The ts-mixer package provides a convenient feature to extend multiple classes at once. At first, install the package to your project:

npm i ts-mixer  

Extend Multiple Classes

Now that you installed the ts-mixer package, go ahead and use it in your app.

The following code snippet is a preview of how Supercharge composes the base testing utility. Individual classes implement features like HTTP testing or faking data and the base test should extend all classes to make them available for the user.

const Many = require('ts-mixer')  
const RenderViews = require('./concerns/render-views')  
const FakeData = require('./concerns/creates-fake-data')  
const MakeHttpRequests = require('./concerns/makes-http-requests')

class BaseTest extends Many(RenderViews, FakeData, MakeHttpRequests) {  
  constructor () {
    super()

    this
      .methodFromRenderViews()
      .methodFromFakeData()
      .methodFromMakeHttpRequests()
  }
}

module.exports = BaseTest  

Pass all classes as separate arguments to the import of extends-classes and it will do the inheritance. Notice that I’ve imported extends-classes as Many.

That’s it!

Enjoy coding & make it rock!


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