Function createToHaveReturnedMatcher

packages/expect/src/spyMatchers.ts:414–478

()

  };

const createToHaveReturnedMatcher = (): MatcherFunction<[unknown]> =>
  function (received: any, expected): SyncExpectationResult {
    const expectedArgument = '';
    const options: MatcherHintOptions = {
      isNot: this.isNot,
      promise: this.promise,
    };
    ensureNoExpected(expected, 'toHaveReturned', options);
    ensureMock(received, 'toHaveReturned', expectedArgument, options);

    const receivedName = received.getMockName();

    // Count return values that correspond only to calls that returned
    const count = received.mock.results.reduce(
      (n: number, result: any) => (result.type === 'return' ? n + 1 : n),
      0,
    );

    const pass = count > 0;

    const message = pass
      ? () =>
          // eslint-disable-next-line prefer-template
          matcherHint(
            'toHaveReturned',
            receivedName,
            expectedArgument,
            options,
          ) +
          '\n\n' +
          `Expected number of returns: ${printExpected(0)}\n` +
          `Received number of returns: ${printReceived(count)}\n\n` +
          received.mock.results
            .reduce((lines: Array<string>, result: any, i: number) => {
              if (result.type === 'return' && lines.length < PRINT_LIMIT) {
                lines.push(`${i + 1}: ${printReceived(result.value)}`);
              }

              return lines;
            }, [])
            .join('\n') +
          (received.mock.calls.length === count
            ? ''
            : `\n\nReceived number of calls:   ${printReceived(
                received.mock.calls.length,
              )}`)
      : () =>
          // eslint-disable-next-line prefer-template
          matcherHint(
            'toHaveReturned',
            receivedName,
            expectedArgument,
            options,
          ) +
          '\n\n' +
          `Expected number of returns: >= ${printExpected(1)}\n` +
          `Received number of returns:    ${printReceived(count)}` +
          (received.mock.calls.length === count