TypeError: loginScreen.visibleOfWelcome is not a function

I want to access method defined in the javascript class. While running the code, I am getting error as

TypeError: loginScreen.visibleOfWelcome is not a function

This is my code : firstPage.CCC.js

module.exports = class LoginScreen {

    get welcome() {
      return element(by.id("welcome"));
    }


    visibleOfWelcome() {
       expect(this.welcome).toBeVisible();
    }

  }

firstTest.specs.js

var loginScreen = require("./firstPage.CCC.js");

describe('Example', () => {
  beforeEach(async () => {
    await device.reloadReactNative();
  });

    it('should have welcome screen', async () => {
      await loginScreen.visibleOfWelcome();
    });
  })

If I write await loginScreen.visibleOfWelcome(); then I get an error as

TypeError: loginScreen.visibleOfWelcome is not a function

if write await loginScreen.visibleOfWelcome; then my code works file.

Any idea why ? I want to call as await loginScreen.visibleOfWelcome();

Try below solution:

export class LoginScreen {

    get welcome() {
      return element(by.id("welcome"));
    }


    visibleOfWelcome() {
       expect(this.welcome).toBeVisible();
    }

  }

Now here you can do this:

var LoginScreen = require("./firstPage.CCC");
var loginScreen= new LoginScreen();

describe('Example', () => {
  beforeEach(async () => {
    await device.reloadReactNative();
  });

    it('should have welcome screen', async () => {
      await loginScreen.visibleOfWelcome();
    });
  })

Hope it will work for you.