toThrowMatchers.ts

/**
 * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

import {formatStackTrace, separateMessageFromStack} from 'jest-message-util';
import {
  EXPECTED_COLOR,
  MatcherHintOptions,
  RECEIVED_COLOR,
  matcherErrorMessage,
  matcherHint,
  printDiffOrStringify,
  printExpected,
  printReceived,
  printWithType,
} from 'jest-matcher-utils';
import {
  printExpectedConstructorName,
  printExpectedConstructorNameNot,
  printReceivedConstructorName,
  printReceivedConstructorNameNot,
  printReceivedStringContainExpectedResult,
  printReceivedStringContainExpectedSubstring,
} from './print';
import type {
  ExpectationResult,
  MatcherState,
  MatchersObject,
  RawMatcherFn,
  SyncExpectationResult,
} from './types';
import {isError} from './utils';

const DID_NOT_THROW = 'Received function did not throw';

type Thrown =
  | {
      hasMessage: true;
      isError: true;
      message: string;
      value: Error;
    }
  | {
      hasMessage: boolean;
      isError: false;
      message: string;
      value: any;
    };

const getThrown = (e: any): Thrown => {
  const hasMessage =
    e !== null && e !== undefined && typeof e.message === 'string';

  if (hasMessage && typeof e.name === 'string' && typeof e.stack === 'string') {
    return {
      hasMessage,
      isError: true,
      message: e.message,
      value: e,
    };
  }

  return {
    hasMessage,
    isError: false,
    message: hasMessage ? e.message : String(e),
    value: e,
  };
};

export const createMatcher = (
  matcherName: string,
  fromPromise?: boolean,
): RawMatcherFn =>
  // eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
  function (
    this: MatcherState,
    received: Function,
    expected: any,
  ): ExpectationResult {
    const options = {
      isNot: this.isNot,
      promise: this.promise,
    };

    let thrown = null;

    if (fromPromise && isError(received)) {
      thrown = getThrown(received);
    } else {
      if (typeof received !== 'function') {
        if (!fromPromise) {
          const placeholder = expected === undefined ? '' : 'expected';
          throw new Error(
            matcherErrorMessage(
              matcherHint(matcherName, undefined, placeholder, options),
              `${RECEIVED_COLOR('received')} value must be a function`,
              printWithType('Received', received, printReceived),
            ),
          );
        }
      } else {
        try {
          received();
        } catch (e) {
          thrown = getThrown(e);
        }
      }
    }

    if (expected === undefined) {
      return toThrow(matcherName, options, thrown);
    } else if (typeof expected === 'function') {
      return toThrowExpectedClass(matcherName, options, thrown, expected);
    } else if (typeof expected === 'string') {
      return toThrowExpectedString(matcherName, options, thrown, expected);
    } else if (expected !== null && typeof expected.test === 'function') {
      return toThrowExpectedRegExp(matcherName, options, thrown, expected);
    } else if (
      expected !== null &&
      typeof expected.asymmetricMatch === 'function'
    ) {
      return toThrowExpectedAsymmetric(matcherName, options, thrown, expected);
    } else if (expected !== null && typeof expected === 'object') {
      return toThrowExpectedObject(matcherName, options, thrown, expected);
    } else {
      throw new Error(
        matcherErrorMessage(
          matcherHint(matcherName, undefined, undefined, options),
          `${EXPECTED_COLOR(
            'expected',
          )} value must be a string or regular expression or class or error`,
          printWithType('Expected', expected, printExpected),
        ),
      );
    }
  };

const matchers: MatchersObject = {
  toThrow: createMatcher('toThrow'),
  toThrowError: createMatcher('toThrowError'),
};

const toThrowExpectedRegExp = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
  expected: RegExp,
): SyncExpectationResult => {
  const pass = thrown !== null && expected.test(thrown.message);

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected pattern: not ', expected) +
        (thrown !== null && thrown.hasMessage
          ? formatReceived(
              'Received message:     ',
              thrown,
              'message',
              expected,
            ) + formatStack(thrown)
          : formatReceived('Received value:       ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected pattern: ', expected) +
        (thrown === null
          ? '\n' + DID_NOT_THROW
          : thrown.hasMessage
          ? formatReceived('Received message: ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Received value:   ', thrown, 'value'));

  return {message, pass};
};

type AsymmetricMatcher = {
  asymmetricMatch: (received: unknown) => boolean;
};

const toThrowExpectedAsymmetric = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
  expected: AsymmetricMatcher,
): SyncExpectationResult => {
  const pass = thrown !== null && expected.asymmetricMatch(thrown.value);

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected asymmetric matcher: not ', expected) +
        '\n' +
        (thrown !== null && thrown.hasMessage
          ? formatReceived('Received name:    ', thrown, 'name') +
            formatReceived('Received message: ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Thrown value: ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected asymmetric matcher: ', expected) +
        '\n' +
        (thrown === null
          ? DID_NOT_THROW
          : thrown.hasMessage
          ? formatReceived('Received name:    ', thrown, 'name') +
            formatReceived('Received message: ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Thrown value: ', thrown, 'value'));

  return {message, pass};
};

const toThrowExpectedObject = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
  expected: Error,
): SyncExpectationResult => {
  const pass = thrown !== null && thrown.message === expected.message;

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected message: not ', expected.message) +
        (thrown !== null && thrown.hasMessage
          ? formatStack(thrown)
          : formatReceived('Received value:       ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        (thrown === null
          ? formatExpected('Expected message: ', expected.message) +
            '\n' +
            DID_NOT_THROW
          : thrown.hasMessage
          ? printDiffOrStringify(
              expected.message,
              thrown.message,
              'Expected message',
              'Received message',
              true,
            ) +
            '\n' +
            formatStack(thrown)
          : formatExpected('Expected message: ', expected.message) +
            formatReceived('Received value:   ', thrown, 'value'));

  return {message, pass};
};

const toThrowExpectedClass = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
  expected: Function,
): SyncExpectationResult => {
  const pass = thrown !== null && thrown.value instanceof expected;

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        printExpectedConstructorNameNot('Expected constructor', expected) +
        (thrown !== null &&
        thrown.value != null &&
        typeof thrown.value.constructor === 'function' &&
        thrown.value.constructor !== expected
          ? printReceivedConstructorNameNot(
              'Received constructor',
              thrown.value.constructor,
              expected,
            )
          : '') +
        '\n' +
        (thrown !== null && thrown.hasMessage
          ? formatReceived('Received message: ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Received value: ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        printExpectedConstructorName('Expected constructor', expected) +
        (thrown === null
          ? '\n' + DID_NOT_THROW
          : (thrown.value != null &&
            typeof thrown.value.constructor === 'function'
              ? printReceivedConstructorName(
                  'Received constructor',
                  thrown.value.constructor,
                )
              : '') +
            '\n' +
            (thrown.hasMessage
              ? formatReceived('Received message: ', thrown, 'message') +
                formatStack(thrown)
              : formatReceived('Received value: ', thrown, 'value')));

  return {message, pass};
};

const toThrowExpectedString = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
  expected: string,
): SyncExpectationResult => {
  const pass = thrown !== null && thrown.message.includes(expected);

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected substring: not ', expected) +
        (thrown !== null && thrown.hasMessage
          ? formatReceived(
              'Received message:       ',
              thrown,
              'message',
              expected,
            ) + formatStack(thrown)
          : formatReceived('Received value:         ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, undefined, options) +
        '\n\n' +
        formatExpected('Expected substring: ', expected) +
        (thrown === null
          ? '\n' + DID_NOT_THROW
          : thrown.hasMessage
          ? formatReceived('Received message:   ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Received value:     ', thrown, 'value'));

  return {message, pass};
};

const toThrow = (
  matcherName: string,
  options: MatcherHintOptions,
  thrown: Thrown | null,
): SyncExpectationResult => {
  const pass = thrown !== null;

  const message = pass
    ? () =>
        matcherHint(matcherName, undefined, '', options) +
        '\n\n' +
        (thrown !== null && thrown.hasMessage
          ? formatReceived('Error name:    ', thrown, 'name') +
            formatReceived('Error message: ', thrown, 'message') +
            formatStack(thrown)
          : formatReceived('Thrown value: ', thrown, 'value'))
    : () =>
        matcherHint(matcherName, undefined, '', options) +
        '\n\n' +
        DID_NOT_THROW;

  return {message, pass};
};

const formatExpected = (label: string, expected: unknown) =>
  label + printExpected(expected) + '\n';

const formatReceived = (
  label: string,
  thrown: Thrown | null,
  key: string,
  expected?: string | RegExp,
) => {
  if (thrown === null) {
    return '';
  }

  if (key === 'message') {
    const message = thrown.message;

    if (typeof expected === 'string') {
      const index = message.indexOf(expected);
      if (index !== -1) {
        return (
          label +
          printReceivedStringContainExpectedSubstring(
            message,
            index,
            expected.length,
          ) +
          '\n'
        );
      }
    } else if (expected instanceof RegExp) {
      return (
        label +
        printReceivedStringContainExpectedResult(
          message,
          typeof expected.exec === 'function' ? expected.exec(message) : null,
        ) +
        '\n'
      );
    }

    return label + printReceived(message) + '\n';
  }

  if (key === 'name') {
    return thrown.isError
      ? label + printReceived(thrown.value.name) + '\n'
      : '';
  }

  if (key === 'value') {
    return thrown.isError ? '' : label + printReceived(thrown.value) + '\n';
  }

  return '';
};

const formatStack = (thrown: Thrown | null) =>
  thrown === null || !thrown.isError
    ? ''
    : formatStackTrace(
        separateMessageFromStack(thrown.value.stack!).stack,
        {
          rootDir: process.cwd(),
          testMatch: [],
        },
        {
          noStackTrace: false,
        },
      );

export default matchers;