feat: add support for flat configs (#789)

* feat: add support for flat configs

* ci: fix release replacements

* chore(release): 6.2.0-next.1 [skip ci]

# [6.2.0-next.1](v6.1.1...v6.2.0-next.1) (2024-03-13)

### Features

* add support for flat configs ([901d52a](901d52a))

* fix: build types

* fix: improve types

* chore(release): 6.2.0-next.2 [skip ci]

# [6.2.0-next.2](v6.2.0-next.1...v6.2.0-next.2) (2024-03-14)

### Bug Fixes

* build types ([054a862](054a862))
* improve types ([2340489](2340489))

* feat: move flat configs to new "flat" subpackage

* ci: fix release

* chore(release): 6.2.0-next.3 [skip ci]

# [6.2.0-next.3](v6.2.0-next.2...v6.2.0-next.3) (2024-03-14)

### Features

* move flat configs to new "flat" subpackage ([1d3533f](1d3533f))

---------

Co-authored-by: semantic-release-bot <[email protected]>

Author: RebeccaStevens

.eslintrc.json

@@ -119,6 +119,7 @@
         "@typescript-eslint/no-unused-vars": "off",
         "@typescript-eslint/prefer-function-type": "off",
         "@typescript-eslint/consistent-generic-constructors": "off",
+        "import/extensions": "off",
         "import/no-unresolved": "off",
         "init-declarations": "off",
         "jsdoc/require-jsdoc": "off",

.releaserc.yml

@@ -51,11 +51,35 @@ plugins:
           from: "\\$\\{__VERSION__\\}"
           to: "${nextRelease.version}"
           results:
-            - file: "./lib/index.js"
+            - file: "./lib/classic.cjs"
               hasChanged: true
               numMatches: 1
               numReplacements: 1
-            - file: "./lib/index.mjs"
+            - file: "./lib/classic.d.cts"
+              hasChanged: false
+              numMatches: 0
+              numReplacements: 0
+            - file: "./lib/classic.d.mts"
+              hasChanged: false
+              numMatches: 0
+              numReplacements: 0
+            - file: "./lib/classic.mjs"
+              hasChanged: true
+              numMatches: 1
+              numReplacements: 1
+            - file: "./lib/flat.cjs"
+              hasChanged: true
+              numMatches: 1
+              numReplacements: 1
+            - file: "./lib/flat.d.cts"
+              hasChanged: false
+              numMatches: 0
+              numReplacements: 0
+            - file: "./lib/flat.d.mts"
+              hasChanged: false
+              numMatches: 0
+              numReplacements: 0
+            - file: "./lib/flat.mjs"
               hasChanged: true
               numMatches: 1
               numReplacements: 1

CHANGELOG.md

@@ -30,6 +30,17 @@ pnpm add -D eslint @typescript-eslint/parser eslint-plugin-functional
 
 ## Usage
 
+### Flat Config
+
+If using the new [flat config](https://eslint.org/docs/latest/use/configure/configuration-files-new),
+import from `eslint-plugin-functional/flat`.
+
+```ts
+import functional from "eslint-plugin-functional/flat";
+```
+
+### Classic Config
+
 Add `functional` to the plugins section of your `.eslintrc` configuration file. Then configure the rules you want to use under the rules section.
 
 ```jsonc

GETTING_STARTED.md

@@ -33,7 +33,7 @@ Tidelift is working with the maintainers of `eslint-plugin-functional` and a gro
 
 ## Rulesets
 
-The following rulesets are made available by this plugin:
+The following rulesets are made available by this plugin.
 
 Presets:
 

README.md

@@ -3,7 +3,25 @@ import { format } from "prettier";
 
 export default {
   configEmoji: [["lite", "☑️"]],
-  ignoreConfig: ["all", "off", "disable-type-checked"],
+  ignoreConfig: [
+    "all",
+    "off",
+    "disable-type-checked",
+    "flat/all",
+    "flat/currying",
+    "flat/disable-type-checked",
+    "flat/external-typescript-recommended",
+    "flat/external-vanilla-recommended",
+    "flat/lite",
+    "flat/no-exceptions",
+    "flat/no-mutations",
+    "flat/no-other-paradigms",
+    "flat/no-statements",
+    "flat/off",
+    "flat/recommended",
+    "flat/strict",
+    "flat/stylistic",
+  ],
   ruleDocSectionInclude: ["Rule Details"],
   ruleListSplit: "meta.docs.category",
   postprocess: (doc) => format(doc, { parser: "markdown" }),

eslint-doc-generator.config.ts

@@ -1,6 +1,11 @@
 {
   "$schema": "node_modules/knip/schema-jsonc.json",
-  "entry": ["src/index.ts!", "tests/**/*.test.ts", "cz-adapter/index.js"],
+  "entry": [
+    "src/flat.ts!",
+    "src/classic.ts!",
+    "tests/**/*.test.ts",
+    "cz-adapter/index.js",
+  ],
   "project": ["src/**/*.ts!", "tests/**/*.ts", "cz-adapter/**/*.{js,ts}"],
   "ignore": ["tests/fixture/file.ts"],
   "ignoreDependencies": ["@types/eslint", "@vitest/coverage-istanbul"],

knip.jsonc

@@ -34,10 +34,25 @@
     "Jonas Kello"
   ],
   "exports": {
-    "import": "./lib/index.mjs",
-    "require": "./lib/index.cjs"
+    ".": {
+      "types": {
+        "import": "./lib/classic.d.mts",
+        "require": "./lib/classic.d.cts"
+      },
+      "import": "./lib/classic.mjs",
+      "require": "./lib/classic.cjs"
+    },
+    "./flat": {
+      "types": {
+        "import": "./lib/flat.d.mts",
+        "require": "./lib/flat.d.cts"
+      },
+      "import": "./lib/flat.mjs",
+      "require": "./lib/flat.cjs"
+    }
   },
-  "main": "lib/index.cjs",
+  "main": "lib/classic.cjs",
+  "types": "lib/classic.d.cts",
   "files": [
     "lib/",
     "package.json",

package.json

@@ -12,17 +12,17 @@ const treeshake = {
   unknownGlobalSideEffects: false,
 } satisfies RollupOptions["treeshake"];
 
-const library = {
-  input: "src/index.ts",
+const classic = {
+  input: "src/classic.ts",
 
   output: [
     {
-      file: pkg.exports.import,
+      file: pkg.exports["."].import,
       format: "esm",
       sourcemap: false,
     },
     {
-      file: pkg.exports.require,
+      file: pkg.exports["."].require,
       format: "cjs",
       sourcemap: false,
     },
@@ -42,4 +42,34 @@ const library = {
   treeshake,
 } satisfies RollupOptions;
 
-export default [library];
+const flat = {
+  input: "src/flat.ts",
+
+  output: [
+    {
+      file: pkg.exports["./flat"].import,
+      format: "esm",
+      sourcemap: false,
+    },
+    {
+      file: pkg.exports["./flat"].require,
+      format: "cjs",
+      sourcemap: false,
+    },
+  ],
+
+  plugins: [
+    rollupPluginAutoExternal(),
+    rollupPluginTs({
+      transpileOnly: true,
+      tsconfig: "tsconfig.build.json",
+    }),
+    rollupPluginDeassert({
+      include: ["**/*.{js,ts}"],
+    }),
+  ],
+
+  treeshake,
+} satisfies RollupOptions;
+
+export default [classic, flat];

rollup.config.ts

@@ -15,25 +15,33 @@ import recommended from "#eslint-plugin-functional/configs/recommended";
 import strict from "#eslint-plugin-functional/configs/strict";
 import stylistic from "#eslint-plugin-functional/configs/stylistic";
 import { rules } from "#eslint-plugin-functional/rules";
+import { ruleNameScope } from "#eslint-plugin-functional/utils/misc";
 
-const config: Linter.Plugin = {
+export default {
   rules,
   configs: {
-    all,
-    lite,
-    recommended,
-    strict,
-    off,
-    "disable-type-checked": disableTypeChecked,
-    "external-vanilla-recommended": externalVanillaRecommended,
-    "external-typescript-recommended": externalTypeScriptRecommended,
-    currying,
-    "no-exceptions": noExceptions,
-    "no-mutations": noMutations,
-    "no-other-paradigms": noOtherParadigms,
-    "no-statements": noStatements,
-    stylistic,
+    all: { plugins: [ruleNameScope], rules: all },
+    lite: { plugins: [ruleNameScope], rules: lite },
+    recommended: { plugins: [ruleNameScope], rules: recommended },
+    strict: { plugins: [ruleNameScope], rules: strict },
+    off: { plugins: [ruleNameScope], rules: off },
+    "disable-type-checked": {
+      plugins: [ruleNameScope],
+      rules: disableTypeChecked,
+    },
+    "external-vanilla-recommended": {
+      plugins: [ruleNameScope],
+      rules: externalVanillaRecommended,
+    },
+    "external-typescript-recommended": {
+      plugins: [ruleNameScope],
+      rules: externalTypeScriptRecommended,
+    },
+    currying: { plugins: [ruleNameScope], rules: currying },
+    "no-exceptions": { plugins: [ruleNameScope], rules: noExceptions },
+    "no-mutations": { plugins: [ruleNameScope], rules: noMutations },
+    "no-other-paradigms": { plugins: [ruleNameScope], rules: noOtherParadigms },
+    "no-statements": { plugins: [ruleNameScope], rules: noStatements },
+    stylistic: { plugins: [ruleNameScope], rules: stylistic },
   },
-};
-
-export default config;
+} as Linter.Plugin;

src/index.ts renamed to src/classic.ts

@@ -1,45 +1,15 @@
-import { type Linter } from "@typescript-eslint/utils/ts-eslint";
+import { type FlatConfig } from "@typescript-eslint/utils/ts-eslint";
 
-import * as functionalParameters from "#eslint-plugin-functional/rules/functional-parameters";
-import * as immutableData from "#eslint-plugin-functional/rules/immutable-data";
-import * as noClasses from "#eslint-plugin-functional/rules/no-classes";
-import * as noConditionalStatements from "#eslint-plugin-functional/rules/no-conditional-statements";
-import * as noExpressionStatements from "#eslint-plugin-functional/rules/no-expression-statements";
-import * as noLet from "#eslint-plugin-functional/rules/no-let";
-import * as noLoopStatements from "#eslint-plugin-functional/rules/no-loop-statements";
-import * as noMixedTypes from "#eslint-plugin-functional/rules/no-mixed-types";
-import * as noPromiseReject from "#eslint-plugin-functional/rules/no-promise-reject";
-import * as noReturnVoid from "#eslint-plugin-functional/rules/no-return-void";
-import * as noThisExpressions from "#eslint-plugin-functional/rules/no-this-expressions";
-import * as noThrowStatements from "#eslint-plugin-functional/rules/no-throw-statements";
-import * as noTryStatements from "#eslint-plugin-functional/rules/no-try-statements";
-import * as preferImmutableTypes from "#eslint-plugin-functional/rules/prefer-immutable-types";
-import * as preferPropertySignatures from "#eslint-plugin-functional/rules/prefer-property-signatures";
-import * as preferTacit from "#eslint-plugin-functional/rules/prefer-tacit";
-import * as readonlyType from "#eslint-plugin-functional/rules/readonly-type";
-import * as typeDeclarationImmutability from "#eslint-plugin-functional/rules/type-declaration-immutability";
+import { rules } from "#eslint-plugin-functional/rules";
+import { ruleNameScope } from "#eslint-plugin-functional/utils/misc";
 
-const config: Linter.Config = {
-  rules: {
-    [`functional/${functionalParameters.name}`]: "error",
-    [`functional/${immutableData.name}`]: "error",
-    [`functional/${noClasses.name}`]: "error",
-    [`functional/${noConditionalStatements.name}`]: "error",
-    [`functional/${noExpressionStatements.name}`]: "error",
-    [`functional/${noLet.name}`]: "error",
-    [`functional/${noLoopStatements.name}`]: "error",
-    [`functional/${noMixedTypes.name}`]: "error",
-    [`functional/${noPromiseReject.name}`]: "error",
-    [`functional/${noReturnVoid.name}`]: "error",
-    [`functional/${noThisExpressions.name}`]: "error",
-    [`functional/${noThrowStatements.name}`]: "error",
-    [`functional/${noTryStatements.name}`]: "error",
-    [`functional/${preferImmutableTypes.name}`]: "error",
-    [`functional/${preferPropertySignatures.name}`]: "error",
-    [`functional/${preferTacit.name}`]: "warn",
-    [`functional/${readonlyType.name}`]: "error",
-    [`functional/${typeDeclarationImmutability.name}`]: "error",
-  },
-};
-
-export default config;
+export default {
+  ...Object.fromEntries(
+    Object.entries(rules)
+      .filter(([, rule]) => rule.meta.deprecated !== true)
+      .map(([name, rule]) => [
+        `${ruleNameScope}/${name}`,
+        rule.meta.docs.recommendedSeverity,
+      ]),
+  ),
+} satisfies FlatConfig.Config["rules"];

src/configs/all.ts

@@ -1,11 +1,18 @@
-import { type Linter } from "@typescript-eslint/utils/ts-eslint";
+import { type FlatConfig } from "@typescript-eslint/utils/ts-eslint";
 
-import * as functionalParameters from "#eslint-plugin-functional/rules/functional-parameters";
+import { rules } from "#eslint-plugin-functional/rules";
+import { ruleNameScope } from "#eslint-plugin-functional/utils/misc";
 
-const config: Linter.Config = {
-  rules: {
-    [`functional/${functionalParameters.name}`]: "error",
-  },
-};
-
-export default config;
+export default Object.fromEntries(
+  Object.entries(rules)
+    .filter(
+      ([, rule]) =>
+        rule.meta.deprecated !== true &&
+        rule.meta.docs.category === "Currying" &&
+        rule.meta.docs.recommended !== false,
+    )
+    .map(([name, rule]) => [
+      `${ruleNameScope}/${name}`,
+      rule.meta.docs.recommendedSeverity,
+    ]),
+) satisfies FlatConfig.Config["rules"];