CHANGELOG.md

@fluidframework/eslint-config-fluid Changelog

2.90.0

Dependency updates only.

2.83.0

Dependency updates only.

2.82.0

Dependency updates only.

2.81.0

Dependency updates only.

2.80.0

Dependency updates only.

2.74.0

Dependency updates only.

Unreleased

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

Modular Structure

The configuration is now organized into a modular structure under library/:

• library/constants.mts - Shared constants (ignores, file patterns, import restrictions)
• library/settings.mts - Plugin settings (import-x, jsdoc)
• library/rules/ - Rule definitions organized by config level (base, minimal-deprecated, recommended, strict)
• library/configs/ - Config builders and shared overrides

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 9 Flat Config Support

This package now supports ESLint 9 flat config format via a new flat.mjs export. The flat config wraps existing configs using FlatCompat from @eslint/eslintrc for backward compatibility.

Key features:

• New flat.mjs module exports recommended, strict, and minimalDeprecated configs for ESLint 9
• Automatic handling of type-aware parsing configuration for JavaScript files and test files
• Generated eslint.config.mjs files for all packages in the repository
• Script to regenerate flat configs: pnpm tsx scripts/generate-flat-eslint-configs.ts

Packages can now use eslint.config.mjs instead of .eslintrc.cjs, but the legacy .eslintrc.cjs format remains supported for backward compatibility. Migration is optional and not required.

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 downgraded to "warn" (until ESLint 9 migration completes):

• 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

recommended -> minimal

• @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 */.

9.0.0

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

The package now uses rules from @eslint-community/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

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

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

The package now uses rules from 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

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
• @typescript-eslint/no-unsafe-function-type
• @typescript-eslint/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
• no-empty-interface

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

• no-empty-object-type
• no-unsafe-function-type
• no-wrapper-object-types

6.1.1

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

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
• @typescript-eslint/no-unsafe-function-type
• @typescript-eslint/no-wrapper-object-types

6.0.1

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

Adds the following @typescript-eslint/no-restricted-imports rules:

1. Prefer using strict 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

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

• @typescript-eslint/consistent-type-exports
• @typescript-eslint/consistent-type-imports
• @typescript-eslint/no-import-type-side-effects

5.7.4

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

/**
 * 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

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:

     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

Disabled the unicorn/no-array-push-push rule, which reports false positives for methods named "push" on non-array objects.

5.6.0

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.:

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

instead of:

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

5.5.1

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

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
• unicorn/number-literal-case

The following rules have been disabled for test code:

• unicorn/prefer-module

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

• unicorn/no-useless-spread

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

The allowExpressions option for the @typescript-eslint/explicit-function-return-type rule has been set to true.

@typescript-eslint/no-explicit-any changes

The 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

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

[
	"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, with the node resolver taking precedence.

The precedence has been reversed in this release: 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

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

5.1.0

Enables new API trimming rules.

5.0.0

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

4.0.0

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

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

Enable the import-no-deprecated rule

The import/no-deprecated rule is now enabled for all configs except test files.