Function toContainEqual

packages/expect/src/matchers.ts:569–614

(received: ContainIterable, expected: unknown)

  },

  toContainEqual(received: ContainIterable, expected: unknown) {
    const matcherName = 'toContainEqual';
    const isNot = this.isNot;
    const options: MatcherHintOptions = {
      comment: 'deep equality',
      isNot,
      promise: this.promise,
    };

    if (received == null) {
      throw new Error(
        matcherErrorMessage(
          matcherHint(matcherName, undefined, undefined, options),
          `${RECEIVED_COLOR('received')} value must not be null nor undefined`,
          printWithType('Received', received, printReceived),
        ),
      );
    }

    const index = [...received].findIndex(item =>
      equals(item, expected, [...this.customTesters, iterableEquality]),
    );
    const pass = index !== -1;

    const message = () => {
      const labelExpected = 'Expected value';
      const labelReceived = `Received ${getType(received)}`;
      const printLabel = getLabelPrinter(labelExpected, labelReceived);

      return (
        // eslint-disable-next-line prefer-template
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        `${printLabel(labelExpected)}${isNot ? 'not ' : ''}${printExpected(
          expected,
        )}\n` +
        `${printLabel(labelReceived)}${isNot ? '    ' : ''}${
          isNot && Array.isArray(received)
            ? printReceivedArrayContainExpectedItem(received, index)
            : printReceived(received)
        }`
      );
    };

    return {message, pass};
  },

  toEqual(received: unknown, expected: unknown) {
    const matcherName = 'toEqual';