playwright/tests/library/events/num-args.spec.ts

// Copyright Joyent, Inc. and other Node contributors.
// Modifications copyright (c) by Microsoft Corporation
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import { EventEmitter } from './utils';
import { test, expect } from '@playwright/test';

test('should work', () => {
  const e = new EventEmitter();
  const num_args_emitted = [];

  e.on('numArgs', (...args) => {
    const numArgs = args.length;
    num_args_emitted.push(numArgs);
  });

  e.on('foo', function() {
    num_args_emitted.push(arguments.length);
  });

  e.on('foo', function() {
    num_args_emitted.push(arguments.length);
  });

  e.emit('numArgs');
  e.emit('numArgs', null);
  e.emit('numArgs', null, null);
  e.emit('numArgs', null, null, null);
  e.emit('numArgs', null, null, null, null);
  e.emit('numArgs', null, null, null, null, null);

  e.emit('foo', null, null, null, null);

  expect(Array.isArray(num_args_emitted)).toBeTruthy();
  expect(num_args_emitted).toHaveLength(8);
  expect(num_args_emitted[0]).toEqual(0);
  expect(num_args_emitted[1]).toEqual(1);
  expect(num_args_emitted[2]).toEqual(2);
  expect(num_args_emitted[3]).toEqual(3);
  expect(num_args_emitted[4]).toEqual(4);
  expect(num_args_emitted[5]).toEqual(5);
  expect(num_args_emitted[6]).toEqual(4);
  expect(num_args_emitted[6]).toEqual(4);
});