Can a javascript class return another class?-CodePudding

Is it a bad practice to return a class inside the method of another class?

Example: createBlockClass method

class BlockBuilder {
    constructor (methodForBlock) {
        this.methodForBlock = methodForBlock;
    };

    createBlockClass () {
        const method = this.methodForBlock.bind(this.methodForBlock);
        return class Block {
            constructor(title) {
                this.title = title;
            };
            method = method;
        }
    }
};

const blockBuilder = new BlockBuilder(() => console.log('Hello, world!!!'));
const Block = blockBuilder.createBlockClass();
const block1 = new Block("block one");
const block2 = new Block("block two");
block1.method();
block2.method();

I need to receive a method as a parameter and add it to the block class before creating any instance

CodePudding user response：

You can use a function to create a class:

function createBlockClass(methodForBlock) {
  return class Block {
    constructor(title) {
      this.title = title;
    }
    method = methodForBlock;
  }
}

const Block = createBlockClass(() => console.log('Hello, world!!!'));

const block1 = new Block("block one");
const block2 = new Block("block two");

block1.method();
block2.method();

Hope it helps.

CodePudding user response：

A class in javascript is a function sprinkled with syntactic sugar. (reason: in javascript 'prototypal inheritance instead of the "regular" class-based inheritance as in e.g. python, java).

A function in javascript is a first-class citizen, so a function can be both the input, as well as the output of another function.

This leads to the following deductions/conclusions:

A function can output another function.

A function can output a class.

A class can output another class.

I hope this will help.