Creating a TypeScript mixin with a partial class is a useful technique that allows you to

Question

Creating a TypeScript mixin with a partial class is a useful technique that allows you to

I am attempting to have class A inherit properties from class B without using the extends keyword. To achieve this, I am utilizing a mixin in the following manner:

class A{
 someProp: String
 someMethod(){}
}

class B implements classA{
  someProp: String
  someMethod: () => void;
}

However, I want to avoid having to redeclare all the properties and methods in classA, so I am experimenting with the Partial keyword like so:

class B implements Partial<classA>{}

Unfortunately, when I try this approach, the TypeScript compiler throws an error:

A class may only implement another class or interface

Does anyone have suggestions on how I can resolve this issue?

typescript

Answer 1

Answer №1

Implement the mixin pattern by utilizing the extends keyword. In this method, define A as a mixin.

type Constructor<T = {}> = new (...args: any[]) => T;

function A<C extends Constructor>(Base: C) {
  return class extends Base {
    someProp: String
    someMethod(){}
  }

class B extends A(class {}) {}

Alternatively, if you prefer, utilize declaration merging to duplicate the public interface of A onto B.

class B {}
interface B extends A {}
Object.assign(B.prototype, A.prototype); // copy methods during runtime

The mixin strategy is generally preferred, unless there is a specific reason not to use it.

Answer 2

Implement the mixin pattern by utilizing the extends keyword. In this method, define A as a mixin.

type Constructor<T = {}> = new (...args: any[]) => T;

function A<C extends Constructor>(Base: C) {
  return class extends Base {
    someProp: String
    someMethod(){}
  }

class B extends A(class {}) {}

Alternatively, if you prefer, utilize declaration merging to duplicate the public interface of A onto B.

class B {}
interface B extends A {}
Object.assign(B.prototype, A.prototype); // copy methods during runtime

The mixin strategy is generally preferred, unless there is a specific reason not to use it.

Creating a TypeScript mixin with a partial class is a useful technique that allows you to

Answer №1

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