jest-27-expect-message

🃏🗯

Add custom message to Jest expects (with support for Jest 27+). This is a drop in replacement for jest-expect-message.

The original jest-expect-message will throw this error when used in newer versions of Jest:
``



"TypeError: matcherResult.message is not a function"





Version 1.0.4 is fully compatible with

jest-expect-message

. Starting in version 1.1.0, I'll start including new features and improvement.s



If

jest-expect-message

 is updated to support Jest 27+, this package will be marked as deprecated.









![Build Status](https://travis-ci.org/mattphillips/jest-expect-message)

![Code Coverage](https://codecov.io/github/mattphillips/jest-expect-message)

![version](https://www.npmjs.com/package/jest-expect-message)

![downloads](http://npm-stat.com/charts.html?package=jest-expect-message&from=2017-09-14)

![MIT License](https://github.com/mattphillips/jest-expect-message/blob/master/LICENSE)

![PRs Welcome](http://makeapullrequest.com)

![Roadmap](https://github.com/mattphillips/jest-expect-message/blob/master/docs/ROADMAP.md)

![Examples](https://github.com/mattphillips/jest-expect-message/blob/master/docs/EXAMPLES.md)



Problem



In many testing libraries it is possible to supply a custom message for a given expectation, this is currently not

possible in Jest.



For example:

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});





This will throw the following error in Jest:

sh

Expect takes at most one argument.





Solution

jest-27-expect-message allows you to call expect with a second argument of a String

 message.



For example the same test as above:

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});





With

jest-27-expect-message

 this will fail with your custom error message:

sh

  ● returns 2 when adding 1 and 1



    Custom message:

      Woah this should be 2!



    expect(received).toBe(expected) // Object.is equality



    Expected: 3

    Received: 2





Installation



With npm:

sh

npm install --save-dev jest-27-expect-message





With yarn:

sh

yarn add -D jest-27-expect-message





Setup



Add

jest-27-expect-message to your Jest setupFilesAfterEnv

 configuration.

See for help



$3

json

"jest": {

  "setupFilesAfterEnv": ["jest-27-expect-message"]

}

$3

json

"jest": {

  "setupTestFrameworkScriptFile": "jest-27-expect-message"

}





Usage



 -

expect(actual, message)

actual: The value you would normally pass into an expect

 to assert against with a given matcher.

   -

message: String, the custom message you want to be printed should the expect

 fail.

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});

Contributors

_{Matt Phillips}
💻 📖 💡 🤔 🚇") ⚠️ 🔧 |
| :---: |

LICENSE

MIT

jest-27-expect-message



"TypeError: matcherResult.message is not a function"





Version 1.0.4 is fully compatible with

jest-expect-message

. Starting in version 1.1.0, I'll start including new features and improvement.s



If

jest-expect-message

 is updated to support Jest 27+, this package will be marked as deprecated.









![Build Status](https://travis-ci.org/mattphillips/jest-expect-message)

![Code Coverage](https://codecov.io/github/mattphillips/jest-expect-message)

![version](https://www.npmjs.com/package/jest-expect-message)

![downloads](http://npm-stat.com/charts.html?package=jest-expect-message&from=2017-09-14)

![MIT License](https://github.com/mattphillips/jest-expect-message/blob/master/LICENSE)

![PRs Welcome](http://makeapullrequest.com)

![Roadmap](https://github.com/mattphillips/jest-expect-message/blob/master/docs/ROADMAP.md)

![Examples](https://github.com/mattphillips/jest-expect-message/blob/master/docs/EXAMPLES.md)



Problem



In many testing libraries it is possible to supply a custom message for a given expectation, this is currently not

possible in Jest.



For example:

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});





This will throw the following error in Jest:

sh

Expect takes at most one argument.





Solution

jest-27-expect-message allows you to call expect with a second argument of a String

 message.



For example the same test as above:

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});





With

jest-27-expect-message

 this will fail with your custom error message:

sh

  ● returns 2 when adding 1 and 1



    Custom message:

      Woah this should be 2!



    expect(received).toBe(expected) // Object.is equality



    Expected: 3

    Received: 2





Installation



With npm:

sh

npm install --save-dev jest-27-expect-message





With yarn:

sh

yarn add -D jest-27-expect-message





Setup



Add

jest-27-expect-message to your Jest setupFilesAfterEnv

 configuration.

See for help



$3

json

"jest": {

  "setupFilesAfterEnv": ["jest-27-expect-message"]

}

$3

json

"jest": {

  "setupTestFrameworkScriptFile": "jest-27-expect-message"

}





Usage



 -

expect(actual, message)

actual: The value you would normally pass into an expect

 to assert against with a given matcher.

   -

message: String, the custom message you want to be printed should the expect

 fail.

js

test('returns 2 when adding 1 and 1', () => {

  expect(1 + 1, 'Woah this should be 2!').toBe(3);

});

Contributors

_{Matt Phillips}
💻 📖 💡 🤔 🚇") ⚠️ 🔧 |
| :---: |

LICENSE

MIT