call a methods of a class without using NEW keyword inside other class node js-CodePudding

I want to access Main class methods to another Person class without creating a new instance Is it possible?? Can we access it without creating an instance of a class

let myInstance = new Person();

 class Main {
      constructor(args) {
        this.hooks = [];
      }
      add_hooks(name, func) {
        if (!this.hooks[name]) this.hooks[name] = [];
        this.hooks[name].push(func);
      }
      call_hooks(name, ...params) {
        if (this.hooks[name]) this.hooks[name].forEach((func) => func(...params));
      }
    }

other class Person how to access without using new keyword

const Main = require("./main.js");
class Person {
  exec() {
    const action =  Main();
    action.add_hook("jump", console.log.bind(console, "this will log "));
  }
}

CodePudding user response：

If you're not planning on instantiating the object, and you don't care about having multiple instances with each having their own state, you don't need a class.

Just create individual functions, or export an object.

const hooks = [];

export function add_hooks(name, func) {
  if (!hooks[name]) hooks[name] = [];
  hooks[name].push(func);
}

export function call_hooks(name, ...params) {
  if (!hooks[name]) return;
  for (const func of this.hooks[name]) {
    func(...params);
  }
}

It's possible too to do this with static methods, and that would be the likely answer if you write Java where everything has to be a class, but I wouldn't recommended it in Javascript.

CodePudding user response：

There is no big magic to it. Since the OP just wants to reuse prototypal Main methods, one is going to explicitly delegate the method/s of interest which was/were provided/accessed before via Main.prototype ...

class Main {
  constructor(args) {
    this.hooks = {};
  }
  add_hooks(name, func) {
    if (!this.hooks[name]) {
      this.hooks[name] = [];
    }
    this.hooks[name].push(func);
  }
  call_hooks(name, ...params) {
    if (this.hooks[name]) {
      this.hooks[name].forEach(func => func(...params));
    }
  }
}

// const Main = require("./main.js");

class Person {

  // // ... either add `hooks` as public property at instantiation time ...
  // hooks = {};

  exec() {
    const ref = Main.prototype;
    ref.add_hooks.call(this, "jump", console.log.bind(console, "this will log"));
  }
}

// ... or add `hooks` via additional glue code ...
function createPersonWithHooksAndExecute() {
  const type = new Person();

  type.hooks = {};
  type.exec();

  return type;
}
const someone = createPersonWithHooksAndExecute();
console.log({ someone });

// this will log
Main.prototype.call_hooks.call(someone, "jump");

.as-console-wrapper { min-height: 100%!important; top: 0; }