use biome

.devcontainer/devcontainer.json

@@ -1,26 +1,19 @@
 {
-	"name": "Misskey",
-	"dockerComposeFile": "docker-compose.yml",
-	"service": "app",
-	"workspaceFolder": "/workspace",
-	"features": {
-		"ghcr.io/devcontainers/features/node:1": {
-			"version": "20"
-		},
-		"ghcr.io/devcontainers-contrib/features/corepack:1": {}
-	},
-	"forwardPorts": [3000],
-	"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"
-			]
-		}
-	}
+  "name": "Misskey",
+  "dockerComposeFile": "docker-compose.yml",
+  "service": "app",
+  "workspaceFolder": "/workspace",
+  "features": {
+    "ghcr.io/devcontainers/features/node:1": {
+      "version": "20"
+    },
+    "ghcr.io/devcontainers-contrib/features/corepack:1": {}
+  },
+  "forwardPorts": [3000],
+  "postCreateCommand": "sudo chmod 755 .devcontainer/init.sh && .devcontainer/init.sh",
+  "customizations": {
+    "vscode": {
+      "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',