eslint-plugin-promise

Enforce best practices for JavaScript promises.


- Installation
- Usage
- Rules
- Maintainers
- License

Installation

You'll first need to install ESLint:

``sh
npm install eslint --save-dev
`

Next, install eslint-plugin-promise:

`sh
npm install eslint-plugin-promise --save-dev
`

Note: If you installed ESLint globally (using the -g flag) then you must
also install eslint-plugin-promise globally.

Usage

Add promise to the plugins section of your .eslintrc.json configuration
file. You can omit the eslint-plugin- prefix:

`json
{
"plugins": ["promise"]
}
`

Then configure the rules you want to use under the rules section.

`json
{
"rules": {
"promise/always-return": "error",
"promise/no-return-wrap": "error",
"promise/param-names": "error",
"promise/catch-or-return": "error",
"promise/no-native": "off",
"promise/no-nesting": "warn",
"promise/no-promise-in-callback": "warn",
"promise/no-callback-in-promise": "warn",
"promise/avoid-new": "warn",
"promise/no-new-statics": "error",
"promise/no-return-in-finally": "warn",
"promise/valid-params": "warn",
"promise/no-multiple-resolved": "error"
}
}
`

or start with the recommended rule set:

- eslint.config.js:

`js
import pluginPromise from 'eslint-plugin-promise'
export default [
// ...
pluginPromise.configs['flat/recommended'],
]
`

- .eslintrc.*:

`json
{
"extends": ["plugin:promise/recommended"]
}
`

Rules

💼 Configurations enabled in.\
⚠️ Configurations set to warn in.\
🚫 Configurations disabled in.\
✅ Set in the flat/recommended configuration.\
✅ Set in the recommended configuration.\
🔧 Automatically fixable by the
--fix CLI option.

| Name                      | Description | 💼 | ⚠️ | 🚫 | 🔧 |
| :------------------------------------------------------------------- | :----------------------------------------------------------------------------------------- | :-- | :-- | :-- | :-- |
| always-return | Require returning inside each then() to create readable and reusable Promise chains. | ✅ | | | |
| avoid-new | Disallow creating new promises outside of utility libs (use [util.promisify][] instead). | | | ✅ | |
| catch-or-return | Enforce the use of catch() on un-returned promises. | ✅ | | | |
| no-callback-in-promise | Disallow calling cb() inside of a then() (use [util.callbackify][] instead). | | ✅ | | |
| no-multiple-resolved | Disallow creating new promises with paths that resolve multiple times. | | | | |
| no-native | Require creating a Promise constructor before using it in an ES5 environment. | | | ✅ | |
| no-nesting | Disallow nested then() or catch() statements. | | ✅ | | |
| no-new-statics | Disallow calling new on a Promise static method. | ✅ | | | 🔧 |
| no-promise-in-callback | Disallow using promises inside of callbacks. | | ✅ | | |
| no-return-in-finally | Disallow return statements in finally(). | | ✅ | | |
| no-return-wrap | Disallow wrapping values in Promise.resolve or Promise.reject when not needed. | ✅ | | | |
| param-names | Enforce consistent param names and ordering when creating new promises. | ✅ | | | |
| prefer-await-to-callbacks | Prefer async/await to the callback pattern. | | | | |
| prefer-await-to-then | Prefer await to then()/catch()/finally() for reading Promise values. | | | | |
| prefer-catch | Prefer catch to then(a, b)/then(null, b)` for handling errors. | | | | 🔧 |
| spec-only | Disallow use of non-standard Promise static methods. | | | | |
| valid-params | Enforces the proper number of arguments are passed to Promise functions. | | ✅ | | |

Maintainers

- Jamund Ferguson - [@xjamundx][]
- Macklin Underdown - [@macklinu][]
- Aadit M Shah - [@aaditmshah][]

License

- (c) MMXV jden - ISC license.
- (c) 2016 Jamund Ferguson - ISC license.

[util.callbackify]:
https://nodejs.org/docs/latest/api/util.html#utilcallbackifyoriginal
[util.promisify]: https://nodejs.org/api/util.html#util_util_promisify_original
[@aaditmshah]: https://github.com/aaditmshah
[@macklinu]: https://github.com/macklinu
[@xjamundx]: https://github.com/xjamundx