jest-chain
🃏⛓
Chain Jest matchers together to create one powerful assertion
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[](https://codecov.io/github/mattphillips/jest-chain)
[](https://www.npmjs.com/package/jest-chain)
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[](https://github.com/mattphillips/jest-chain/blob/master/LICENSE)
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[](https://github.com/mattphillips/jest-chain/blob/master/docs/ROADMAP.md)
[](https://github.com/mattphillips/jest-chain/blob/master/docs/EXAMPLES.md)
* 🍸 Less code duplication
* 🤗 Chain core and custom matchers together
* 👾 Expressive assertions
* 🚨 Fail fast assertions
## Problem
Often in [Jest](https://facebook.github.io/jest/) when you are writing tests you may want to perform multiple assertions on the
same variable. Currently to achieve this you have to write an individual `expect` for each
assertion.
For example:
```js
it('add 1 and 1', () => {
const actual = 1 + 1;
expect(actual).toBe(2);
expect(actual).toBeGreaterThan(1);
expect(actual).toBeLessThan(3);
});
```
With `jest-chain` this can instead be written by chaining the matchers together:
```js
it('add 1 and 1', () => {
expect(1 + 1)
.toBe(2)
.toBeGreaterThan(1)
.toBeLessThan(3);
});
```
## Installation
With npm:
```sh
npm install --save-dev jest-chain
```
With yarn:
```sh
yarn add -D jest-chain
```
## Setup
Add `jest-chain` to your Jest `setupFilesAfterEnv` configuration. [See for help](https://jestjs.io/docs/en/next/configuration#setupfilesafterenv-array)
### Jest >v24
```json
"jest": {
"setupFilesAfterEnv": ["jest-chain"]
}
```
### Jest