ESLint flat config migration: diff review (old .eslintrc.cjs → new eslint.config.mts)

azure/packages/azure-local-service/eslint.config.mts

@@ -3,9 +3,9 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	extends: [require.resolve("@fluidframework/eslint-config-fluid/strict"), "prettier"],
-	parserOptions: {
-		project: ["./tsconfig.eslint.json"],
-	},
-};
+import type { Linter } from "eslint";
+import { strict } from "../../../common/build/eslint-config-fluid/flat.mts";
+
+const config: Linter.Config[] = [...strict];
+
+export default config;

azure/packages/azure-service-utils/eslint.config.mts

@@ -3,33 +3,36 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	extends: [require.resolve("@fluidframework/eslint-config-fluid/strict"), "prettier"],
-	parserOptions: {
-		project: ["./tsconfig.json", "./src/test/tsconfig.json"],
-	},
-	rules: {
-		"import-x/no-unassigned-import": "off",
-		"@typescript-eslint/strict-boolean-expressions": "off",
+import type { Linter } from "eslint";
+import { strict } from "../../../common/build/eslint-config-fluid/flat.mts";
+
+const config: Linter.Config[] = [
+	...strict,
+	{
+		rules: {
+			"import-x/no-unassigned-import": "off",
+			"@typescript-eslint/strict-boolean-expressions": "off",
 
-		// Useful for developer accessibility
-		"unicorn/prevent-abbreviations": [
-			"error",
-			{
-				allowList: {
-					// Industry-standard index variable name.
-					i: true,
+			// Useful for developer accessibility
+			"unicorn/prevent-abbreviations": [
+				"error",
+				{
+					allowList: {
+						// Industry-standard index variable name.
+						i: true,
+					},
 				},
-			},
-		],
+			],
+		},
 	},
-	overrides: [
-		{
-			// Overrides for type-tests
-			files: ["src/test/types/*"],
-			rules: {
-				"unicorn/prevent-abbreviations": "off",
-			},
+
+	// Overrides for type-tests
+	{
+		files: ["src/test/types/*"],
+		rules: {
+			"unicorn/prevent-abbreviations": "off",
 		},
-	],
-};
+	},
+];
+
+export default config;

build-tools/packages/build-cli/eslint.config.mts

@@ -3,120 +3,30 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	plugins: ["@typescript-eslint"],
-	extends: [
-		"oclif",
-		"oclif-typescript",
-		// eslint-disable-next-line node/no-extraneous-require
-		require.resolve("@fluidframework/eslint-config-fluid/recommended"),
-		"prettier",
-	],
-	parserOptions: {
-		project: ["./tsconfig.json", "./src/test/tsconfig.json"],
-	},
-	rules: {
-		// TODO: Enable and fix violations
-		"@fluid-internal/fluid/no-unchecked-record-access": "warn",
-
-		// Catch unused variables in at lint time instead of compile time
-		"@typescript-eslint/no-unused-vars": "error",
-
-		// This rule is often triggered when using custom Flags, so disabling.
-		"object-shorthand": "off",
-
-		// This package is exclusively used in a Node.js context
-		"import-x/no-nodejs-modules": "off",
-
-		// oclif uses default exports for commands
-		"import-x/no-default-export": "off",
-
-		// Set to warn because we're not ready to enforce this rule for much of build-cli yet. It is enabled for new code.
-		"import-x/no-deprecated": "warn",
-
-		"import-x/no-internal-modules": [
-			"error",
-			{
-				allow: [
-					// fs-extra's ./esm export is needed for ESM support.
-					"fs-extra/esm",
-
-					// This package uses interfaces and types that are not exposed directly by npm-check-updates.
-					"npm-check-updates/build/src/types/**",
-
-					// We call oclif commands' run method directly in some cases, so these are all excluded.
-					"**/commands/**",
+import { baseConfig } from "../../eslint.config.base.mts";
 
-					// These are all excluded because they're "submodules" used for organization.
-					// AB#8118 tracks removing the barrel files and importing directly from the submodules.
-					"**/library/**",
-					"**/handlers/**",
-					"**/machines/**",
-					"**/repoPolicyCheck/**",
-					"**/azureDevops/**",
-					"**/codeCoverage/**",
-					"azure-devops-node-api/**",
-				],
-			},
-		],
-
-		// Superseded by Biome
-		"import/order": "off",
-
-		"jsdoc/multiline-blocks": [
-			"error",
-			{
-				noSingleLineBlocks: true,
-			},
-		],
-
-		// The default for this rule is 4, but 5 is better
-		"max-params": ["warn", 5],
-
-		// Too strict for our needs
-		"unicorn/filename-case": "off",
-
-		// In commands, destructuring is useful in some places but makes others less legible, so consistency isn't preferred.
-		"unicorn/consistent-destructuring": "off",
-
-		// Deprecated in 2018: https://eslint.org/blog/2018/11/jsdoc-end-of-life/
-		"valid-jsdoc": "off",
-
-		// Disable all perfectionist rules that are inherited from oclif's lint config.
-		"perfectionist/sort-array-includes": "off",
-		"perfectionist/sort-astro-attributes": "off",
-		"perfectionist/sort-classes": "off",
-		"perfectionist/sort-enums": "off",
-		"perfectionist/sort-exports": "off",
-		"perfectionist/sort-imports": "off",
-		"perfectionist/sort-interfaces": "off",
-		"perfectionist/sort-intersection-types": "off",
-		"perfectionist/sort-jsx-props": "off",
-		"perfectionist/sort-maps": "off",
-		"perfectionist/sort-named-exports": "off",
-		"perfectionist/sort-named-imports": "off",
-		"perfectionist/sort-object-types": "off",
-		"perfectionist/sort-objects": "off",
-		"perfectionist/sort-svelte-attributes": "off",
-		"perfectionist/sort-union-types": "off",
-		"perfectionist/sort-vue-attributes": "off",
+export default [
+	...baseConfig,
+	// Ignore test data files and test fixtures that aren't in tsconfig
+	{
+		ignores: ["src/test/data/**", "src/test/**/fixtures/**"],
 	},
-	overrides: [
-		{
-			// Rules only for test files
-			files: ["*.spec.ts", "src/test/**"],
-			rules: {
-				// Test files can import from anywhere
-				"import-x/no-internal-modules": "off",
-			},
+	{
+		rules: {
+			// This rule is often triggered when using custom Flags, so disabling.
+			"object-shorthand": "off",
+
+			// The default for this rule is 4, but 5 is better.
+			// TODO: AB#58055 Consider lowering this limit and simplifying build-tools code accordingly.
+			"max-params": ["warn", 5],
 		},
-		{
-			// Rules only for files that are built on the build-infrastructure APIs.
-			files: ["src/**/vnext/**"],
-			rules: {
-				// Set to error since code using build-infrastructure APIs should not need to use any deprecated APIs.
-				"import-x/no-deprecated": "error",
-			},
+	},
+	{
+		// Rules only for files that are built on the build-infrastructure APIs.
+		files: ["src/**/vnext/**"],
+		rules: {
+			// Set to error since code using build-infrastructure APIs should not need to use any deprecated APIs.
+			"import-x/no-deprecated": "error",
 		},
-	],
-};
+	},
+];

build-tools/packages/build-infrastructure/eslint.config.mts

@@ -3,39 +3,17 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	plugins: ["@typescript-eslint", "chai-friendly"],
-	extends: [
-		// eslint-disable-next-line node/no-extraneous-require
-		require.resolve("@fluidframework/eslint-config-fluid/recommended"),
-		"prettier",
-	],
-	parserOptions: {
-		project: ["./tsconfig.json", "./src/test/tsconfig.json"],
-	},
-	rules: {
-		// Catch unused variables in at lint time instead of compile time
-		"@typescript-eslint/no-unused-vars": "error",
-
-		// This package is exclusively used in a Node.js context
-		"import-x/no-nodejs-modules": "off",
+import { baseConfig, chaiFriendlyConfig } from "../../eslint.config.base.mts";
 
-		"tsdoc/syntax": ["warn"],
+export default [
+	...baseConfig,
+	// Ignore test data files
+	{
+		ignores: ["src/test/data/**"],
 	},
-	overrides: [
-		{
-			// Rules only for test files
-			files: ["*.spec.ts", "src/test/**"],
-			rules: {
-				// Test files can import from anywhere
-				"import-x/no-internal-modules": "off",
-
-				// Superseded by chai-friendly/no-unused-expressions
-				"no-unused-expressions": "off",
-				"@typescript-eslint/no-unused-expressions": "off",
-
-				"chai-friendly/no-unused-expressions": "error",
-			},
-		},
-	],
-};
+	// Chai-friendly rules for test files
+	{
+		files: ["**/*.spec.ts", "src/test/**"],
+		...chaiFriendlyConfig,
+	},
+];

build-tools/packages/build-tools/eslint.config.mts

@@ -3,26 +3,70 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended", "prettier"],
-	plugins: ["@typescript-eslint"],
-	parser: "@typescript-eslint/parser",
-	parserOptions: {
-		project: ["./tsconfig.json", "./src/test/tsconfig.json"],
+import { baseConfig } from "../../eslint.config.base.mts";
+
+export default [
+	...baseConfig,
+	// Ignore test data files
+	{
+		ignores: ["src/test/data/**"],
 	},
-	rules: {
-		// TODO: Enable these ASAP
-		"@typescript-eslint/no-explicit-any": "off",
-		"@typescript-eslint/no-unsafe-argument": "off",
-		"@typescript-eslint/no-unsafe-assignment": "off",
-		"@typescript-eslint/no-unsafe-call": "off",
-		"@typescript-eslint/no-unsafe-member-access": "off",
+	{
+		rules: {
+			// build-tools uses some template-like tokens for use in configs
+			"no-template-curly-in-string": "off",
+
+			// TODO: AB#58049 Enable these type-safety rules ASAP and fix violations
+			"@typescript-eslint/no-explicit-any": "off",
+			"@typescript-eslint/no-unsafe-argument": "off",
+			"@typescript-eslint/no-unsafe-assignment": "off",
+			"@typescript-eslint/no-unsafe-call": "off",
+			"@typescript-eslint/no-unsafe-member-access": "off",
+
+			"@typescript-eslint/no-non-null-assertion": "error",
 
-		"@typescript-eslint/no-non-null-assertion": "error",
+			// Allow empty object types for extending interfaces
+			"@typescript-eslint/no-empty-object-type": "off",
 
-		// Catch unused variables in at lint time instead of compile time
-		"@typescript-eslint/no-unused-vars": "error",
+			// Allow require imports for dynamic loading
+			"@typescript-eslint/no-require-imports": "off",
 
-		"@typescript-eslint/switch-exhaustiveness-check": "error",
+			// TODO: AB#58050 These rules require code changes - enable and fix violations
+			"@typescript-eslint/class-literal-property-style": "off",
+			"@typescript-eslint/return-await": "off",
+			"@typescript-eslint/dot-notation": "off",
+			"@typescript-eslint/no-restricted-imports": "off",
+			"@typescript-eslint/no-misused-promises": "off",
+			"@typescript-eslint/await-thenable": "off",
+			"@typescript-eslint/prefer-string-starts-ends-with": "off",
+			"@typescript-eslint/prefer-includes": "off",
+			"@typescript-eslint/no-dynamic-delete": "off",
+			"@typescript-eslint/prefer-for-of": "off",
+			"@typescript-eslint/only-throw-error": "off",
+			"@typescript-eslint/restrict-plus-operands": "off",
+			"@typescript-eslint/no-extraneous-class": "off",
+			"unicorn/prefer-ternary": "off",
+			"unicorn/better-regex": "off",
+			"jsdoc/check-indentation": "off",
+			"@eslint-community/eslint-comments/no-unused-disable": "off",
+			"@eslint-community/eslint-comments/no-unlimited-disable": "off",
+
+			// TODO: AB#58051 Base ESLint rules that require code changes - enable and fix violations
+			"guard-for-in": "off",
+			"no-restricted-syntax": "off",
+			"eqeqeq": "off",
+			"no-param-reassign": "off",
+			"no-undef-init": "off",
+			"default-case": "off",
+			"radix": "off",
+		},
+	},
+	// Enable switch-exhaustiveness-check only for TS files (not .d.ts which lack type info)
+	{
+		files: ["**/*.ts", "**/*.tsx", "**/*.mts", "**/*.cts"],
+		ignores: ["**/*.d.ts"],
+		rules: {
+			"@typescript-eslint/switch-exhaustiveness-check": "error",
+		},
 	},
-};
+];

build-tools/packages/bundle-size-tools/eslint.config.mts

@@ -3,19 +3,6 @@
  * Licensed under the MIT License.
  */
 
-module.exports = {
-	extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
-	plugins: ["@typescript-eslint"],
-	parser: "@typescript-eslint/parser",
-	parserOptions: {
-		project: ["./tsconfig.json"],
-	},
-	rules: {
-		"@typescript-eslint/switch-exhaustiveness-check": "error",
-		"@typescript-eslint/no-inferrable-types": "off",
-		"@typescript-eslint/no-var-requires": "off",
+import { baseConfig } from "../../eslint.config.base.mts";
 
-		// This package is exclusively used in a Node.js context
-		"import/no-nodejs-modules": "off",
-	},
-};
+export default baseConfig;