Creating an extended class with mandatory properties

Question

Creating an extended class with mandatory properties

In order to streamline code sharing between two classes that overlap, I decided to create a new class called Common.

For one of the subclasses, I needed all the properties from the Common class to be required. My initial thought was to utilize the Required utility type in the following manner:

class A extends Common {
  //...
 }

class B extends Required<Common> {
  //...
 }

Unfortunately, I encountered an error stating that Required is not defined. Is there a straightforward solution to achieve my desired outcome, or should I consider revising the code entirely?

typescript class

Answer 1

Answer №1

To ensure that properties are required, you can utilize extends Common and implement them using implements:

class Common {
  foo?: string;
  bar?: number;
}

class A extends Common {
  //...
 }

class B extends Common implements Required<Common> {
  constructor(
    public foo: string,
    public bar: number,
  ) {
    super();
  }
 }

Interactive Example

Answer 2

To ensure that properties are required, you can utilize extends Common and implement them using implements:

class Common {
  foo?: string;
  bar?: number;
}

class A extends Common {
  //...
 }

class B extends Common implements Required<Common> {
  constructor(
    public foo: string,
    public bar: number,
  ) {
    super();
  }
 }

Interactive Example

Creating an extended class with mandatory properties

Answer №1

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