[Feature]: Is there a reason not to expose MatcherReturnType?

[silversonicaxel]

🚀 Feature Request

Can this type definition here

playwright/utils/generate_types/overrides-test.d.ts

Lines 412 to 419 in 021c5c1

	type MatcherReturnType = {
	message: () => string;
	pass: boolean;
	name?: string;
	expected?: unknown;
	actual?: any;
	log?: string[];
	};

be exported?

type MatcherReturnType = {
  message: () => string;
  pass: boolean;
  name?: string;
  expected?: unknown;
  actual?: any;
  log?: string[];
};

Example

export type MatcherReturnType = {
  message: () => string;
  pass: boolean;
  name?: string;
  expected?: unknown;
  actual?: any;
  log?: string[];
};

Motivation

It can be useful in case of expect extensions. Currently we need to define this type internally.

[pavelfeldman]

Could you share your use case? We rather seek for the answer to "is there a reason to expose". I.e. by default we'd like to expose nothing, unless necessary.

[silversonicaxel]

Imagine the example in this page https://playwright.dev/docs/test-assertions#add-custom-matchers-using-expectextend.

I can copy here a smaller version of this case example, to show the need of matcher return type, from Playwright exported type definition:

export const expect = baseExpect.extend({
  async toHaveAmount(locator: Locator, expected: number): Promise<MatcherReturnType> {
    let pass: boolean;
    try {
      await baseExpect(locator).toHaveAttribute('data-amount', String(expected));
      pass = true;
    } catch (e: any) {
      pass = false;
    }
    const message = () => 'Whatever error is ..';

    return {
      message,
      pass,
      name: 'toHaveAmount',
      expected,
    };
  },
});

It would be nice to import MatcherReturnType instead of defining it myself.

[silversonicaxel]

Thanks

[HardworkingSlacker]

If you need this type in an older version of Playwright, this construction should provide you with the correct type:

type MatcherReturnType = Awaited<Parameters<Expect["extend"]> extends [matchers: Record<string, (...args: any[]) => infer MRT>] ? MRT : any>;