@fluidframework/eslint-config-fluid/CHANGELOG.md

Shareable ESLint config for the Fluid Framework

# @fluidframework/eslint-config-fluid Changelog

## [12.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v12.0.0)

<!-- Add new changelog entries here. -->

## [11.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v11.0.0)

### Breaking: node 22 is now the minimum supported node version

Node 22 is now the minimum supported Node.js version. This aligns with the standing Node upgrade policy as Node 20 reached end-of-life on April 30, 2026.

### Breaking: import-x/order disabled

The `import-x/order` rule has been disabled. Prefer using formatting tools like Biome to handle import sorting.

### Breaking: ESLint 8 legacy configs no longer exported

This package now uses ESLint flat config format exclusively. The legacy `.eslintrc` format is no longer supported.
The package root now exports the named flat and server configs directly from `@fluidframework/eslint-config-fluid`.

**Requirements:**

- ESLint 9 (recommended), or
- ESLint 8.21+ with `ESLINT_USE_FLAT_CONFIG=true` environment variable

**Migration:**

Replace your `.eslintrc.cjs`:

```javascript
// OLD - .eslintrc.cjs (no longer supported)
module.exports = { extends: ["@fluidframework/eslint-config-fluid/strict"] };
```

With `eslint.config.mts`:

```javascript
// NEW - eslint.config.mts
import { strict } from "@fluidframework/eslint-config-fluid";
export default [...strict];
```

For ESLint 8.21+ users, set the environment variable:

```bash
ESLINT_USE_FLAT_CONFIG=true eslint .
```

**Removed files:**

- `base.js`, `minimal-deprecated.js`, `recommended.js`, `strict.js`, `strict-biome.js`, `index.js`

**Removed dependency:**

- `@eslint/eslintrc` (FlatCompat no longer needed)

## [10.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v10.0.0)

### eslint-plugin-react replaced by @eslint-react/eslint-plugin

The `eslint-plugin-react` dependency has been replaced with
[`@eslint-react/eslint-plugin`](https://eslint-react.xyz/) v2.13.0. This change is required because
`eslint-plugin-react` 7.37.5 is incompatible with ESLint 10 (it calls the removed `context.getFilename()` API), and the
upstream fix has been blocked since February 2026.

`@eslint-react/eslint-plugin` v2.13.0 supports ESLint 8, 9, and 10, so this version works with the current ESLint 9
setup and will not block the future ESLint 10 upgrade.

`eslint-plugin-react-hooks` is unchanged — it already supports ESLint 10 and continues to provide React Compiler rules.

#### Breaking: Rule names changed

All `react/*` rules from `eslint-plugin-react` are replaced by `@eslint-react/*` rules. Any `eslint-disable` comments
or per-package rule overrides referencing `react/*` rules must be updated to the new names.

Key rule mapping:

| Old rule (`eslint-plugin-react`)      | New rule (`@eslint-react`)                                                               |
| ------------------------------------- | ---------------------------------------------------------------------------------------- |
| `react/jsx-key`                       | `@eslint-react/no-missing-key`                                                           |
| `react/jsx-no-comment-textnodes`      | `@eslint-react/jsx-no-comment-textnodes`                                                 |
| `react/jsx-no-target-blank`           | `@eslint-react/dom/no-unsafe-target-blank`                                               |
| `react/no-children-prop`              | `@eslint-react/no-children-prop`                                                         |
| `react/no-danger-with-children`       | `@eslint-react/dom/no-dangerously-set-innerhtml-with-children`                           |
| `react/no-deprecated`                 | Multiple rules (see below)                                                               |
| `react/no-direct-mutation-state`      | `@eslint-react/no-direct-mutation-state`                                                 |
| `react/no-find-dom-node`              | `@eslint-react/dom/no-find-dom-node`                                                     |
| `react/no-render-return-value`        | `@eslint-react/dom/no-render-return-value`                                               |
| `react/no-string-refs`                | `@eslint-react/no-string-refs`                                                           |
| `react/no-unstable-nested-components` | `@eslint-react/no-nested-component-definitions`                                          |
| `react/jsx-no-useless-fragment`       | `@eslint-react/no-useless-fragment`                                                      |
| `react/prop-types`                    | `@eslint-react/no-prop-types` (bans PropTypes usage; TypeScript handles prop validation) |

The `react/no-deprecated` rule is replaced by individual rules for each deprecated API:
`@eslint-react/no-component-will-mount`, `@eslint-react/no-component-will-receive-props`,
`@eslint-react/no-component-will-update`, `@eslint-react/no-create-ref`, `@eslint-react/dom/no-find-dom-node`,
`@eslint-react/dom/no-hydrate`, `@eslint-react/dom/no-render`, `@eslint-react/dom/no-render-return-value`.

#### Breaking: Rules removed (no equivalent)

The following rules have no `@eslint-react` equivalent and are no longer enforced:

- `react/no-unescaped-entities` — Low priority; JSX transpilation handles this correctly.
- `react/no-is-mounted` — Legacy class component pattern; TypeScript discourages this.
- `react/require-render-return` — TypeScript enforces return types.

#### New rules enabled

The `recommended-typescript` preset enables many rules not previously configured. These are set at `warn` severity
unless otherwise noted:

- `@eslint-react/no-nested-component-definitions` (`error`) — Catches component definitions inside render functions.
- `@eslint-react/no-array-index-key` — Warns against using array index as key.
- `@eslint-react/no-clone-element` — Warns against `React.cloneElement`.
- `@eslint-react/no-context-provider` — Warns against deprecated `Context.Provider` (React 19).
- `@eslint-react/no-forward-ref` — Warns against deprecated `React.forwardRef` (React 19).
- `@eslint-react/web-api/no-leaked-event-listener` — Catches leaked event listeners.
- `@eslint-react/web-api/no-leaked-interval` — Catches leaked `setInterval` calls.
- `@eslint-react/web-api/no-leaked-timeout` — Catches leaked `setTimeout` calls.
- `@eslint-react/web-api/no-leaked-resize-observer` — Catches leaked resize observers.
- `@eslint-react/naming-convention/*` — React naming convention rules.

#### Settings namespace changed

The `@eslint-react` plugin uses `react-x` for its settings namespace instead of `react`. If you have custom
`settings.react` configuration for React version detection, it should be changed to `settings["react-x"]`. The
`recommended-typescript` preset configures `react-x.version: "detect"` automatically.

### Other new rules

- Adds [no-only-tests/no-only-tests](https://github.com/levibuzolic/eslint-plugin-no-only-tests) rule to ensure tests configured with `.only` are not checked in.

## [9.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v9.0.0)

### Native ESLint 9 Flat Config (No FlatCompat)

The flat config implementation has been refactored to use native ESLint 9 flat config format, removing the dependency on `FlatCompat` from `@eslint/eslintrc`. This provides cleaner configuration and better compatibility with ESLint 9.

#### Flat Config Exports

The `flat.mts` module now exports four configurations:

- `recommended` - The recommended configuration for most projects
- `strict` - Stricter rules for production code
- `minimalDeprecated` - Minimal configuration (deprecated, use recommended)
- `strictBiome` - Strict configuration with Biome formatter compatibility

### Removed Rushstack Dependencies

The following packages have been removed from dependencies:

- `@rushstack/eslint-patch`
- `@rushstack/eslint-plugin-security`

The `@rushstack/eslint-plugin-security` plugin has been removed from all configurations. The `patch/modern-module-resolution.js` file has also been removed as it was only needed to support the `@rushstack/eslint-patch` dependency.

### ESLint Rule Changes

**React Hooks plugin upgraded**: Upgraded from `~5.2.0` to `~7.0.1`, enabling several new React Hooks linting rules.

**New react-hooks rules enabled as `"error"`**:

- `react-hooks/component-hook-factories`
- `react-hooks/config`
- `react-hooks/error-boundaries`
- `react-hooks/gating`
- `react-hooks/globals`
- `react-hooks/preserve-manual-memoization`
- `react-hooks/purity`
- `react-hooks/set-state-in-render`
- `react-hooks/use-memo`

**`react-hooks` rules temporarily set to `"warn"`** (to allow time to address violations before the next major release):

- `react-hooks/rules-of-hooks`: Changed from `"error"` to `"warn"`
- `react-hooks/exhaustive-deps`: Changed from `"error"` to `"warn"`
- `react-hooks/immutability`: New rule set to `"warn"`
- `react-hooks/incompatible-library`: New rule set to `"warn"`
- `react-hooks/refs`: New rule set to `"warn"`
- `react-hooks/set-state-in-effect`: New rule set to `"warn"`
- `react-hooks/static-components`: New rule set to `"warn"`
- `react-hooks/unsupported-syntax`: New rule set to `"warn"`

**New unicorn rules** (enabled as `"error"` by default):

- `unicorn/consistent-empty-array-spread`
- `unicorn/no-anonymous-default-export`
- `unicorn/no-await-in-promise-methods`
- `unicorn/no-invalid-fetch-options`
- `unicorn/no-magic-array-flat-depth`
- `unicorn/no-negation-in-equality-check`
- `unicorn/no-single-promise-in-promise-methods`
- `unicorn/no-unnecessary-polyfills`

**Unicorn rules disabled** (consider enabling in future):

- `unicorn/import-style`: Changed from `"error"` to `"off"`
- `unicorn/consistent-destructuring`: Changed from `"error"` to `"off"`
- `unicorn/no-array-callback-reference`: Changed from `"error"` to `"off"`
    - Yields false positives for calls to `map` methods on non-array types.

**Unicorn rules changed to warnings** (to surface occurrences without breaking builds):

- `unicorn/prefer-at`: Changed from `"off"` to `"warn"`
- `unicorn/prefer-string-raw`: New rule set to `"warn"`
- `unicorn/prefer-string-replace-all`: Changed from `"off"` to `"warn"`
- `unicorn/prefer-structured-clone`: New rule set to `"warn"`

#### Rule promotions

The following rules, which were previously enabled only in the `recommended` config, are now also enabled in the `minimal` config:

- `@typescript-eslint/explicit-function-return-type`
- `@typescript-eslint/no-import-type-side-effects`
- `jsdoc/multiline-blocks`
- `no-empty`

#### Rule modifications

- `jsdoc/multiline-blocks`: Updated to allow single-line comments to be expressed as a single line. E.g. `/** Single-line comment */`.

#### Other new rules

#### [@eslint-community/eslint-comments/require-description](https://eslint-community.github.io/eslint-plugin-eslint-comments/rules/require-description.html)

We recommend that all `eslint-disable` comments include a description explaining why the rule is being disabled.
This rule is currently configured at the `warn` level, so it will emit a warning (which may not fail CI), and is expected to be promoted to an error in the future.

### eslint-plugin-eslint-comments replaced by @eslint-community/eslint-plugin-eslint-comments

The package now uses rules from
[@eslint-community/eslint-plugin-eslint-comments](https://eslint-community.github.io/eslint-plugin-eslint-comments/)
v4.5.0 instead of eslint-plugin-eslint-comments v3.2.0. Integrating this change will require renaming eslint disable
comments and overrides, but the changes are mechanical.

## [8.1.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v8.1.0)

### import-x/order rule simplified

The `import-x/order` rule configuration has been simplified to use basic grouping without alphabetization or newlines-between settings. This provides more flexibility in import ordering while still maintaining consistent grouping of import types.

### Resolver configuration updated

The TypeScript resolver configuration has been updated to work correctly with the repository's build setup. The resolver no longer requires explicit name and options wrapping, and uses the resolver directly.

### no-hyphen-after-jsdoc-tag rule disabled

The `@fluid-internal/fluid/no-hyphen-after-jsdoc-tag` rule has been temporarily disabled pending resolution of ADO work item 29535.

## [8.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v8.0.0)

### eslint-plugin-import replaced by eslint-plugin-import-x

The package now uses rules from [eslint-plugin-import-x](https://github.com/un-ts/eslint-plugin-import-x) instead of
eslint-plugin-import. Integrating this change will require renaming eslint disable comments and overrides, but the
changes are mechanical.

## [7.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v7.0.0)

### New Rules

- `@fluid-internal/fluid/no-hyphen-after-jsdoc-tag`
- `@fluid-internal/fluid/no-file-path-links-in-jsdoc`
- `@fluid-internal/fluid/no-markdown-links-in-jsdoc`
- [@typescript-eslint/no-empty-object-type](https://typescript-eslint.io/rules/no-empty-object-type/)
- [@typescript-eslint/no-unsafe-function-type](https://typescript-eslint.io/rules/no-unsafe-function-type/)
- [@typescript-eslint/no-wrapper-object-types](https://typescript-eslint.io/rules/no-wrapper-object-types/)

### Update TypeScript plugin dependencies

`@typescript-eslint/eslint-plugin` and `@typescript-eslint/parser` have been updated.
These updates includes the deprecation and replacement of a couple of rules that were included in this library.

The following rules have been deprecated and disabled in this library:

- [ban-types](https://typescript-eslint.io/rules/ban-types/)
- [no-empty-interface](https://typescript-eslint.io/rules/no-empty-interface/)

They are replaced by the following new rules, which are now configured as errors in this library:

- [no-empty-object-type](https://typescript-eslint.io/rules/no-empty-object-type/)
- [no-unsafe-function-type](https://typescript-eslint.io/rules/no-unsafe-function-type/)
- [no-wrapper-object-types](https://typescript-eslint.io/rules/no-wrapper-object-types/)

## [6.1.1](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v6.1.1)

Enables the following new rules as warnings (they will be promoted to errors in the next major release):

- `@fluid-internal/fluid/no-hyphen-after-jsdoc-tag`

### 🐞 Bug fixes

Fixes indexing issues in the following rules, which would cause incorrect notification ranges and could cause malformed code fixes:

- `@fluid-internal/fluid/no-file-path-links-in-jsdoc`
- `@fluid-internal/fluid/no-markdown-links-in-jsdoc`

## [6.1.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v6.1.0)

Update dependencies on the following packages:

- `@fluid-tools/eslint-plugin-fluid` (from 0.1.5 to 0.2.0)

Enables the following new rules as warnings (they will be promoted to errors in the next major release):

- `@fluid-internal/fluid/no-file-path-links-in-jsdoc`
- `@fluid-internal/fluid/no-markdown-links-in-jsdoc`
- [@typescript-eslint/no-empty-object-type](https://typescript-eslint.io/rules/no-empty-object-type/)
- [@typescript-eslint/no-unsafe-function-type](https://typescript-eslint.io/rules/no-unsafe-function-type/)
- [@typescript-eslint/no-wrapper-object-types](https://typescript-eslint.io/rules/no-wrapper-object-types/)

## [6.0.1](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v6.0.1)

Update dependencies on the following packages:

- `@typescript-eslint/eslint-plugin` (from 7.0.0 to 7.18.0)
- `@typescript-eslint/parser` (from 7.0.0 to 7.18.0)

## [6.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v6.0.0)

Adds the following [@typescript-eslint/no-restricted-imports](https://typescript-eslint.io/rules/no-restricted-imports/) rules:

1. Prefer using [strict](https://nodejs.org/api/assert.html#strict-assertion-mode) assertions from Node's `assert` library.
    - E.g. prefer `import { strict as assert } from "assert";` over `import assert from "assert";`.
2. Don't import from parent index file.
    - E.g. prefer `import { Foo } from "./Foo.js";` over `import { Foo } from "./index.js";`

## [5.8.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.8.0)

Promotes the following rules from the `strict` ruleset to the `recommended` ruleset:

- [@typescript-eslint/consistent-type-exports](https://typescript-eslint.io/rules/consistent-type-exports/)
- [@typescript-eslint/consistent-type-imports](https://typescript-eslint.io/rules/consistent-type-imports/)
- [@typescript-eslint/no-import-type-side-effects](https://typescript-eslint.io/rules/no-import-type-side-effects/)

## [5.7.4](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.7.4)

Updates the contexts in which `jsdoc/require-jsdoc` is applied to make it less overzealous.
Specifically, removes the "VariableDeclaration" context, which would incorrectly trigger for variables that were not exported.

### Example

```typescript
/**
 * foo
 */
export function foo(): void {
	// Before the fix, because the outer scope, `foo`, was exported, this variable `bar` would be incorrectly flagged as needing a JSDoc/TSDoc comment.
	// After the fix, variables inside exported functions, like `bar`, are no longer flagged.
	const bar = "baz";
	...
}
```

## [5.7.3](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.7.3)

Added support for two new patterns in the no-unchecked-record-access ESLint rule:

1. **Nullish Coalescing Assignment Recognition**
    - The rule now recognizes nullish coalescing assignment (`??=`) as a valid safety check
    - Properties accessed after a nullish coalescing assignment will not trigger warnings

2. **Else Block Assignment Handling**
    - Added detection for property assignments in else blocks of existence checks
    - Example pattern now supported:
        ```typescript
        if ("key" in obj) {
        	// use obj.key
        } else {
        	obj.key = defaultValue;
        	// use obj.key
        }
        ```
    - The rule understands that after the else block assignment, the property is safe to use
    - Works with both direct property access and computed property access

## [5.7.2](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.7.2)

Disabled the [unicorn/no-array-push-push](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/no-array-push-push.md) rule, which reports false positives for methods named "push" on non-array objects.

## [5.6.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.6.0)

### New config for use with Biome linter

A new strict-biome config is available that disables all rules that Biome's recommended config includes.
This config is intended to be used in projects that use both eslint and Biome for linting.
This config is considered experimental.

### Auto-fix behavior change for @typescript-eslint/consistent-type-exports

Update auto-fix policy for `@typescript-eslint/consistent-type-exports` to prefer inline `type` annotations, rather than splitting exports into type-only and non-type-only groups.
This makes it easier to tell at a glance how the auto-fix changes affect individual exports when a list of exports is large.
It also makes it easier to detect issues in edge-cases where the the rule is applied incorrectly.

E.g.:

```typescript
export { type Foo, Bar } from "./baz.js";
```

instead of:

```typescript
export type { Foo } from "./baz.js";
export { Bar } from "./baz.js";
```

## [5.5.1](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.5.1)

### Disabled rules

The formatting-related rules below have been disabled in all configs because we use biome or prettier to enforce
formatting conventions. In addition, most of these rules are now deprecated because linters are decreasing their focus
on formatting-related rules in favor of dedicated formatting tools.

#### typescript-eslint

- @typescript-eslint/comma-spacing
- @typescript-eslint/func-call-spacing
- @typescript-eslint/keyword-spacing
- @typescript-eslint/member-delimiter-style
- @typescript-eslint/object-curly-spacing
- @typescript-eslint/semi
- @typescript-eslint/space-before-function-paren
- @typescript-eslint/space-infix-ops
- @typescript-eslint/type-annotation-spacing

#### eslint

All rules below are deprecated. See <https://eslint.org/docs/latest/rules/#deprecated>

- array-bracket-spacing
- arrow-spacing
- block-spacing
- dot-location
- jsx-quotes
- key-spacing
- space-unary-ops
- switch-colon-spacing

### Better test pattern support

Update rule overrides for test code to better support patterns in the repo.
Namely, adds the allowance to "\*\*/tests" directories.

## [5.4.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.4.0)

### New no-unchecked-record-access rule

Enabled new no-unchecked-record-access rule to enforce safe property access on index signature types.

### Disabled rules

The following rules have been disabled in all configs because they conflict with formatter settings:

- [@typescript-eslint/brace-style](https://typescript-eslint.io/rules/brace-style)
- [unicorn/number-literal-case](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v48.0.1/docs/rules/number-literal-case.md)

The following rules have been disabled for test code:

- [unicorn/prefer-module](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v48.0.1/docs/rules/prefer-module.md)

The following rules have been disabled due to frequency of false-positives reported:

- [unicorn/no-useless-spread](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v48.0.1/docs/rules/no-useless-spread.md)

### @typescript-eslint/explicit-function-return-type changes

The [allowExpressions](https://typescript-eslint.io/rules/explicit-function-return-type/#allowexpressions) option for
the @typescript-eslint/explicit-function-return-type rule has been set to `true`.

### @typescript-eslint/no-explicit-any changes

The [ignoreRestArgs](https://typescript-eslint.io/rules/no-explicit-any#ignorerestargs) option for
the @typescript-eslint/no-explicit-any rule has been set to `true`.

### import/no-internal-modules changes

All imports from @fluid-experimental packages are now permitted.

## [5.3.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.3.0)

The import/order rule is enabled with the following settings:

```json
[
	"error",
	{
		"newlines-between": "always",
		"alphabetize": {
			"order": "asc",
			"caseInsensitive": false
		}
	}
]
```

### eslint-import-resolver-typescript preferred over node

Lint configurations previously specified both the `node` and `typescript` [resolvers](https://github.com/import-js/eslint-plugin-import?tab=readme-ov-file#resolvers), with the `node` resolver taking precedence.

The precedence has been reversed in this release: [eslint-import-resolver-typescript](https://github.com/import-js/eslint-import-resolver-typescript) is now the preferred resolver.

This may result in lint rules dependent on imported _types_ (rather than values) to correctly apply, e.g. `import/no-deprecated`.

### allow-ff-test-exports condition enabled

The typescript import resolver now enables the "allow-ff-test-exports" condition, which adds support for linting files which reference FluidFramework test-only exports,
such as id-compressor and merge-tree.

## [5.2.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.2.0)

The import/order rule is now disabled in all configs.

## [5.1.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.1.0)

Enables new API trimming rules.

## [5.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v5.0.0)

Adds eslint-plugin-fluid to eslint-config-fluid. This new dependency adds new Fluid-specific rules.

## [4.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v4.0.0)

Deprecates this package's `minimal` configuration.
Consumers of that configuration will need to update their imports to refer to the renamed module: `minimal-deprecated.js`.

## [3.0.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v3.0.0)

### Update eslint-related dependencies

eslint has been updated to version ~8.49.0. eslint plugins have also been updated to the latest version.

### Update prettier

prettier has been updated to version ~3.0.3.

### Update #16699 typescript-eslint

typescript-eslint has been updated to version ~6.7.2.

## [2.1.0](https://github.com/microsoft/FluidFramework/releases/tag/eslint-config-fluid_v2.1.0)

### Enable the import-no-deprecated rule

The [import/no-deprecated](https://github.com/import-js/eslint-plugin-import/blob/main/docs/rules/no-deprecated.md) rule
is now enabled for all configs except test files.