# jest-validate

> Generic configuration validation tool that helps you with warnings, errors and deprecation messages as well as showing users examples of correct configuration.

Latest version **30.5.1** (published 2026-09-01) · MIT license · 0 weekly downloads

## Install

```sh
npm install jest-validate
pnpm add jest-validate
yarn add jest-validate
bun add jest-validate
```

## Health

**Score 70/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; recently updated; high maintenance score; popular repo.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 30.5.1 |
| Published | 2026-09-01 |
| First published | 2017-01-08 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | ^18.14.0 \|\| ^20.0.0 \|\| ^22.0.0 \|\| >=24.0.0 |
| Dependencies | 6 |
| Unpacked size | 29.3 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 45475 |
| Maintainers | aaronabramov, simenb, rickhanlonii, openjs-operations, cpojer |

## Links

- npm: https://www.npmjs.com/package/jest-validate
- Repository: https://github.com/jestjs/jest
- Homepage: https://github.com/jestjs/jest#readme
- Issues: https://github.com/jestjs/jest/issues
- npm.io page: https://npm.io/package/jest-validate

## Dependencies (6)

- [chalk](https://npm.io/package/chalk.md) ^4.1.2
- [leven](https://npm.io/package/leven.md) ^3.1.0
- [camelcase](https://npm.io/package/camelcase.md) ^6.3.0
- [@jest/types](https://npm.io/package/@jest/types.md) 30.5.1
- [pretty-format](https://npm.io/package/pretty-format.md) 30.5.1
- [@jest/get-type](https://npm.io/package/@jest/get-type.md) 30.5.0

## Recent versions

- 30.5.1 (latest) — 2026-09-01
- 30.0.0-rc.1 (next) — 2025-06-09
- 30.5.0 — 2026-08-28
- 30.4.1 — 2026-05-08
- 30.4.0 — 2026-05-07
- 30.3.0 — 2026-03-10
- 30.2.0 — 2025-09-28
- 30.1.0 — 2025-08-27
- 30.0.5 — 2025-07-22
- 30.0.2 — 2025-06-19
- 30.0.1 — 2025-06-18
- 30.0.0 — 2025-06-10
- 30.0.0-beta.8 — 2025-06-04
- 30.0.0-beta.7 — 2025-06-04
- 30.0.0-beta.6 — 2025-06-03
- … 222 more at https://npm.io/package/jest-validate/versions

## README

# jest-validate

Generic configuration validation tool that helps you with warnings, errors and deprecation messages as well as showing users examples of correct configuration.

```bash
npm install --save jest-validate
```

## Usage

```js
import {validate} from 'jest-validate';

validate(config, validationOptions); // => {hasDeprecationWarnings: boolean, isValid: boolean}
```

Where `ValidationOptions` are:

```ts
type ValidationOptions = {
  comment?: string;
  condition?: (option: unknown, validOption: unknown) => boolean;
  deprecate?: (
    config: Record<string, unknown>,
    option: string,
    deprecatedOptions: DeprecatedOptions,
    options: ValidationOptions,
  ) => boolean;
  deprecatedConfig?: DeprecatedOptions;
  error?: (
    option: string,
    received: unknown,
    defaultValue: unknown,
    options: ValidationOptions,
    path?: Array<string>,
  ) => void;
  exampleConfig: Record<string, unknown>;
  recursive?: boolean;
  recursiveBlacklist?: Array<string>;
  recursiveDenylist?: Array<string>;
  title?: Title;
  unknown?: (
    config: Record<string, unknown>,
    exampleConfig: Record<string, unknown>,
    option: string,
    options: ValidationOptions,
    path?: Array<string>,
  ) => void;
};

type Title = {
  deprecation?: string;
  error?: string;
  warning?: string;
};
```

`exampleConfig` is the only option required.

## API

By default `jest-validate` will print generic warning and error messages. You can however customize this behavior by providing `options: ValidationOptions` object as a second argument:

Almost anything can be overwritten to suite your needs.

### Options

- `recursiveDenylist` – optional array of string keyPaths that should be excluded from deep (recursive) validation.
- `comment` – optional string to be rendered below error/warning message.
- `condition` – an optional function with validation condition.
- `deprecate`, `error`, `unknown` – optional functions responsible for displaying warning and error messages.
- `deprecatedConfig` – optional object with deprecated config keys.
- `exampleConfig` – the only **required** option with configuration against which you'd like to test.
- `recursive` - optional boolean determining whether recursively compare `exampleConfig` to `config` (default: `true`).
- `title` – optional object of titles for errors and messages.

You will find examples of `condition`, `deprecate`, `error`, `unknown`, and `deprecatedConfig` inside source of this repository, named respectively.

## exampleConfig syntax

`exampleConfig` should be an object with key/value pairs that contain an example of a valid value for each key. A configuration value is considered valid when:

- it matches the JavaScript type of the example value, e.g. `string`, `number`, `array`, `boolean`, `function`, or `object`
- it is `null` or `undefined`
- it matches the Javascript type of any of arguments passed to `MultipleValidOptions(...)`

The last condition is a special syntax that allows validating where more than one type is permissible; see example below. It's acceptable to have multiple values of the same type in the example, so you can also use this syntax to provide more than one example. When a validation failure occurs, the error message will show all other values in the array as examples.

## Examples

Minimal example:

```js
validate(config, {exampleConfig});
```

Example with slight modifications:

```js
validate(config, {
  comment: '  Documentation: http://custom-docs.com',
  deprecatedConfig,
  exampleConfig,
  title: {
    deprecation: 'Custom Deprecation',
    // leaving 'error' and 'warning' as default
  },
});
```

This will output:

#### Warning:

```bash
● Validation Warning:

  Unknown option transformx with value "<rootDir>/node_modules/babel-jest" was found.
  This is either a typing error or a user mistake. Fixing it will remove this message.

  Documentation: http://custom-docs.com
```

#### Error:

```bash
● Validation Error:

  Option transform must be of type:
    object
  but instead received:
    string

  Example:
  {
    "transform": {
      "\\.js$": "<rootDir>/preprocessor.js"
    }
  }

  Documentation: http://custom-docs.com
```

## Example validating multiple types

```js
import {multipleValidOptions} from 'jest-validate';

validate(config, {
  // `bar` will accept either a string or a number
  bar: multipleValidOptions('string is ok', 2),
});
```

#### Error:

```bash
● Validation Error:

  Option foo must be of type:
    string or number
  but instead received:
    array

  Example:
  {
    "bar": "string is ok"
  }

  or

  {
    "bar": 2
  }

  Documentation: http://custom-docs.com
```

#### Deprecation

Based on `deprecatedConfig` object with proper deprecation messages. Note custom title:

```bash
Custom Deprecation:

  Option scriptPreprocessor was replaced by transform, which support multiple preprocessors.

  Jest now treats your current configuration as:
  {
    "transform": {".*": "xxx"}
  }

  Please update your configuration.

  Documentation: http://custom-docs.com
```

## Example validating CLI arguments

```js
import {validate} from 'jest-validate';

validateCLIOptions(argv, {...allowedOptions, deprecatedOptions});
```

If `argv` contains a deprecated option that is not specified in `allowedOptions`, `validateCLIOptions` will throw an error with the message specified in the `deprecatedOptions` config:

```bash
● collectCoverageOnlyFrom:

  Option "collectCoverageOnlyFrom" was replaced by "collectCoverageFrom"

  CLI Options Documentation: https://jestjs.io/docs/en/cli.html
```

If the deprecation option is still listed in the `allowedOptions` config, then `validateCLIOptions` will print the warning without throwing an error.

---
_Source: https://npm.io/package/jest-validate · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._