use biome

.devcontainer/devcontainer.json

@@ -13,14 +13,7 @@
 	"postCreateCommand": "sudo chmod 755 .devcontainer/init.sh && .devcontainer/init.sh",
 	"customizations": {
 		"vscode": {
-			"extensions": [
-				"editorconfig.editorconfig",
-				"dbaeumer.vscode-eslint",
-				"Vue.volar",
-				"Orta.vscode-jest",
-				"dbaeumer.vscode-eslint",
-				"mrmlnc.vscode-json5"
-			]
+			"extensions": ["biomejs.biome", "editorconfig.editorconfig", "Vue.volar", "Orta.vscode-jest", "mrmlnc.vscode-json5"]
 		}
 	}
 }

.editorconfig

@@ -11,5 +11,5 @@ trim_trailing_whitespace = true
 [*.md]
 trim_trailing_whitespace = false
 
-[*.{yml,yaml}]
+[*.{json,yml,yaml}]
 indent_style = space

.github/workflows/lint.yml

@@ -11,14 +11,12 @@ on:
       - packages/frontend/**
       - packages/sw/**
       - packages/misskey-js/**
-      - packages/shared/.eslintrc.js
   pull_request:
     paths:
       - packages/backend/**
       - packages/frontend/**
       - packages/sw/**
       - packages/misskey-js/**
-      - packages/shared/.eslintrc.js
 
 jobs:
   pnpm_install:
@@ -63,7 +61,7 @@ jobs:
         cache: 'pnpm'
     - run: corepack enable
     - run: pnpm i --frozen-lockfile
-    - run: pnpm --filter ${{ matrix.workspace }} run eslint
+    - run: pnpm --filter ${{ matrix.workspace }} run biome ci --reporter=github --max-diagnostics=none
 
   typecheck:
     needs: [pnpm_install]

.vscode/extensions.json

@@ -1,9 +1,3 @@
 {
-	"recommendations": [
-		"editorconfig.editorconfig",
-		"dbaeumer.vscode-eslint",
-		"Vue.volar",
-		"Orta.vscode-jest",
-		"mrmlnc.vscode-json5"
-	]
+  "recommendations": ["biomejs.biome", "editorconfig.editorconfig", "Vue.volar", "Orta.vscode-jest", "mrmlnc.vscode-json5"]
 }

biome.json

@@ -0,0 +1,154 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
+  "vcs": { "enabled": true, "clientKind": "git", "useIgnoreFile": true },
+  "files": {
+    "ignore": [
+      "*.min.js",
+      "api.json",
+      "built",
+      "nsfw-model",
+      "packages/backend/built",
+      "packages/backend/nsfw-model",
+      "packages/frontend/built",
+      "packages/sw/built",
+      "packages/misskey-js/built",
+      "packages/misskey-reversi/built",
+      "packages/misskey-bubble-game/built",
+      "locales/index.d.ts",
+      "packages/misskey-js/generator/api.json"
+    ]
+  },
+  "organizeImports": {
+    "enabled": true
+  },
+  "linter": {
+    "enabled": true,
+    "ignore": ["packages/misskey-js/src/autogen"],
+    "rules": {
+      "recommended": true,
+      "complexity": {
+        "noForEach": "info",
+        "noUselessConstructor": {
+          "level": "info",
+          "fix": "none"
+        },
+        "noUselessLabel": {
+          "level": "info",
+          "fix": "none"
+        },
+        "noUselessUndefinedInitialization": {
+          "level": "info",
+          "fix": "none"
+        },
+        "useArrowFunction": {
+          "level": "info",
+          "fix": "none"
+        },
+        "useLiteralKeys": {
+          "level": "info",
+          "fix": "none"
+        },
+        "useOptionalChain": {
+          "level": "info",
+          "fix": "none"
+        }
+      },
+      "performance": {
+        "noDelete": {
+          "level": "info",
+          "fix": "none"
+        }
+      },
+      "style": {
+        "noCommaOperator": "warn",
+        "noNegationElse": {
+          "level": "off",
+          "fix": "none"
+        },
+        "noNonNullAssertion": {
+          "level": "info",
+          "fix": "none"
+        },
+        "noParameterAssign": "info",
+        "noUselessElse": {
+          "level": "info",
+          "fix": "none"
+        },
+        "useImportType": {
+          "level": "off",
+          "fix": "none"
+        },
+        "useNodejsImportProtocol": {
+          "level": "off",
+          "fix": "none"
+        },
+        "useTemplate": {
+          "level": "warn",
+          "fix": "safe"
+        }
+      },
+      "suspicious": {
+        "noAssignInExpressions": "info",
+        "noConfusingVoidType": {
+          "level": "warn",
+          "fix": "none"
+        },
+        "noDoubleEquals": {
+          "level": "warn",
+          "fix": "none",
+          "options": {
+            "ignoreNull": false
+          }
+        },
+        "noExplicitAny": "warn",
+        "noImplicitAnyLet": "warn"
+      }
+    }
+  },
+  "formatter": {
+    "enabled": true,
+    "lineWidth": 140,
+    "useEditorconfig": true
+  },
+  "javascript": {
+    "formatter": {
+      "arrowParentheses": "asNeeded",
+      "quoteStyle": "single"
+    },
+    "parser": {
+      "unsafeParameterDecoratorsEnabled": true
+    }
+  },
+  "overrides": [
+    {
+      "include": ["packages/backend/migration/*.js", "migration/*.js"],
+      "linter": {
+        "rules": {
+          "style": {
+            "noUnusedTemplateLiteral": {
+              "level": "off",
+              "fix": "none"
+            }
+          }
+        }
+      }
+    },
+    {
+      "include": ["*.vue"],
+      "linter": {
+        "rules": {
+          "style": {
+            "useConst": {
+              "level": "off",
+              "fix": "none"
+            },
+            "useImportType": {
+              "level": "off",
+              "fix": "none"
+            }
+          }
+        }
+      }
+    }
+  ]
+}

lefthook.yml

@@ -0,0 +1,15 @@
+#   Refer for explanation to following link:
+#   https://github.com/evilmartians/lefthook/blob/master/docs/configuration.md
+
+pre-push:
+  commands:
+    check:
+      glob: "*.{js,ts,cjs,mjs,d.cts,d.mts,jsx,tsx,json,jsonc,pug,vue}"
+      run: pnpm dlx @biomejs/biome check --no-errors-on-unmatched --files-ignore-unknown=true --colors=off --diagnostic-level=error {push_files}
+
+pre-commit:
+  commands:
+    check:
+      glob: "*.{js,ts,cjs,mjs,d.cts,d.mts,jsx,tsx,json,jsonc,pug,vue}"
+      run: pnpm dlx @biomejs/biome check --write --no-errors-on-unmatched --files-ignore-unknown=true --colors=off --diagnostic-level=error {staged_files}
+      stage_fixed: true

locales/index.js

@@ -5,13 +5,16 @@
 import * as fs from 'node:fs';
 import * as yaml from 'js-yaml';
 
-const merge = (...args) => args.reduce((a, c) => ({
-	...a,
-	...c,
-	...Object.entries(a)
-		.filter(([k]) => c && typeof c[k] === 'object')
-		.reduce((a, [k, v]) => (a[k] = merge(v, c[k]), a), {})
-}), {});
+const merge = (...args) => args.reduce((a, c) => {
+	for (const [k, v] of Object.entries(c)) {
+		if (typeof v === 'object' && typeof a[k] === 'object') {
+			a[k] = merge(a[k], v);
+		} else {
+			a[k] = v;
+		}
+	}
+	return a;
+}, {});
 
 const languages = [
 	'ar-SA',

package.json

@@ -6,7 +6,7 @@
 		"type": "git",
 		"url": "https://github.com/MisskeyIO/misskey.git"
 	},
-	"packageManager": "pnpm@9.12.3",
+	"packageManager": "pnpm@9.14.2",
 	"workspaces": [
 		"packages/frontend",
 		"packages/backend",
@@ -33,6 +33,8 @@
 		"migrateandstart:docker": "pnpm migrate && exec pnpm start:docker",
 		"watch": "pnpm dev",
 		"dev": "node scripts/dev.mjs",
+		"biome": "biome",
+		"format": "biome check --write",
 		"lint": "pnpm -r lint",
 		"cy:open": "pnpm cypress open --browser --e2e --config-file=cypress.config.ts",
 		"cy:run": "pnpm cypress run",
@@ -68,12 +70,11 @@
 		"typescript": "5.6.3"
 	},
 	"devDependencies": {
+		"@biomejs/biome": "1.9.4",
 		"@types/node": "22.9.1",
-		"@typescript-eslint/eslint-plugin": "7.10.0",
-		"@typescript-eslint/parser": "7.10.0",
 		"cross-env": "7.0.3",
 		"cypress": "13.16.0",
-		"eslint": "8.57.1",
+		"lefthook": "1.8.4",
 		"ncp": "2.0.0",
 		"start-server-and-test": "2.0.8"
 	},

packages/backend/package.json

@@ -1,4 +1,4 @@
 {
 	"name": "backend",
 	"main": "./index.js",
 	"private": true,
@@ -20,8 +20,9 @@
 		"restart": "pnpm build && pnpm start",
 		"dev": "nodemon -w src -e ts,js,mjs,cjs,json --exec \"cross-env NODE_ENV=development pnpm run restart\"",
 		"typecheck": "tsc --noEmit && tsc -p test --noEmit",
-		"eslint": "eslint --quiet \"src/**/*.ts\"",
-		"lint": "pnpm typecheck && pnpm eslint",
+		"biome": "biome",
+		"format": "biome check --write",
+		"lint": "pnpm typecheck && biome check",
 		"jest": "cross-env NODE_ENV=test node --experimental-vm-modules --experimental-import-meta-resolve node_modules/jest/bin/jest.js --forceExit --config jest.config.unit.cjs",
 		"jest:e2e": "cross-env NODE_ENV=test node --experimental-vm-modules --experimental-import-meta-resolve node_modules/jest/bin/jest.js --forceExit --config jest.config.e2e.cjs",
 		"jest-and-coverage": "cross-env NODE_ENV=test node --experimental-vm-modules --experimental-import-meta-resolve node_modules/jest/bin/jest.js --coverage --forceExit --config jest.config.unit.cjs",
@@ -191,8 +192,8 @@
 		"xmlbuilder": "15.1.1"
 	},
 	"devDependencies": {
+		"@biomejs/biome": "1.9.4",
 		"@jest/globals": "29.7.0",
-		"@misskey-dev/eslint-plugin": "1.0.0",
 		"@nestjs/platform-express": "10.4.8",
 		"@simplewebauthn/types": "11.0.0",
 		"@swc/jest": "0.2.37",
@@ -234,12 +235,8 @@
 		"@types/vary": "1.1.3",
 		"@types/web-push": "3.6.4",
 		"@types/ws": "8.5.13",
-		"@typescript-eslint/eslint-plugin": "7.10.0",
-		"@typescript-eslint/parser": "7.10.0",
 		"aws-sdk-client-mock": "4.1.0",
 		"cross-env": "7.0.3",
-		"eslint": "8.57.1",
-		"eslint-plugin-import": "2.31.0",
 		"execa": "9.5.1",
 		"fkill": "^9.0.0",
 		"jest": "29.7.0",

packages/backend/src/core/FileInfoService.ts

@@ -273,7 +273,9 @@ export class FileInfoService {
 			watcher.close();
 		});
 		command.run();
-		for (let i = 1; true; i++) { // eslint-disable-line @typescript-eslint/no-unnecessary-condition
+		let i = 0;
+		while (true) {
+			i++;
 			const current = `${i}.png`;
 			const next = `${i + 1}.png`;
 			const framePath = join(cwd, current);

packages/backend/src/core/activitypub/ApRequestService.ts

@@ -34,6 +34,7 @@ type PrivateKey = {
 	keyId: string;
 };
 
+// biome-ignore lint/complexity/noStaticOnlyClass: utility class
 export class ApRequestCreator {
 	static createSignedPost(args: { key: PrivateKey, url: string, body: string, digest?: string, additionalHeaders: Record<string, string> }): Signed {
 		const u = new URL(args.url);

packages/backend/src/decorators.ts

@@ -20,8 +20,7 @@ export function bindThis(target: any, key: string, descriptor: any) {
 	return {
 		configurable: true,
 		get() {
-			// eslint-disable-next-line no-prototype-builtins
-			if (this === target.prototype || this.hasOwnProperty(key) ||
+			if (this === target.prototype || Object.hasOwn(this, key) ||
         typeof fn !== 'function') {
 				return fn;
 			}

packages/backend/src/misc/acct.ts

@@ -14,6 +14,7 @@ export function parse(acct: string): Acct {
 	return { username: split[0], host: split[1] ?? null };
 }
 
+// biome-ignore lint/suspicious/noShadowRestrictedNames: desired behavior
 export function toString(acct: Acct): string {
 	return acct.host == null ? acct.username : `${acct.username}@${acct.host}`;
 }