Switch from Eslint + Typescript-eslint + Prettier to Biome

.lintstagedrc

@@ -1,4 +1,3 @@
 {
-    "*": "prettier --write",
-    "*.(ts|tsx)": ["eslint --fix"]
+    "*": ["biome check --no-errors-on-unmatched --files-ignore-unknown=true"]
 }

biome.jsonc

@@ -0,0 +1,136 @@
+{
+    "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
+    "vcs": {
+        "enabled": true,
+        "clientKind": "git",
+        "useIgnoreFile": true
+    },
+    "files": {
+        "ignoreUnknown": false,
+        "ignore": []
+    },
+    "formatter": {
+        "enabled": true,
+        "useEditorconfig": true,
+        "formatWithErrors": false,
+        "indentStyle": "space",
+        "indentWidth": 4,
+        "lineEnding": "lf",
+        "lineWidth": 120,
+        "attributePosition": "auto",
+        "bracketSpacing": true
+    },
+    "organizeImports": { "enabled": true },
+    "linter": {
+        "enabled": true,
+        "rules": {
+            "recommended": false,
+            "complexity": {
+                "noExtraBooleanCast": "error",
+                "noMultipleSpacesInRegularExpressionLiterals": "error",
+                "noUselessCatch": "error",
+                "noWith": "error"
+            },
+            "correctness": {
+                "noConstAssign": "error",
+                "noConstantCondition": "error",
+                "noEmptyCharacterClassInRegex": "error",
+                "noEmptyPattern": "error",
+                "noGlobalObjectCalls": "error",
+                "noInnerDeclarations": "error",
+                "noInvalidConstructorSuper": "error",
+                "noNewSymbol": "error",
+                "noNonoctalDecimalEscape": "error",
+                "noPrecisionLoss": "error",
+                "noSelfAssign": "error",
+                "noSetterReturn": "error",
+                "noSwitchDeclarations": "error",
+                "noUndeclaredVariables": "error",
+                "noUnreachable": "error",
+                "noUnreachableSuper": "error",
+                "noUnsafeFinally": "error",
+                "noUnsafeOptionalChaining": "error",
+                "noUnusedLabels": "error",
+                "noUnusedVariables": "error",
+                "useArrayLiterals": "error",
+                "useIsNan": "error",
+                "useValidForDirection": "error",
+                "useYield": "error"
+            },
+            "style": {
+                "noArguments": "error",
+                "noVar": "error",
+                "useBlockStatements": "off",
+                "useConsistentBuiltinInstantiation": "error",
+                "useConst": "error",
+                "useNodejsImportProtocol": "error",
+                "useSingleVarDeclarator": "error",
+                "useThrowOnlyError": "error",
+                "useImportType": "error",
+                "useExportType": "error"
+            },
+            "suspicious": {
+                "noAssignInExpressions": "error",
+                "noAsyncPromiseExecutor": "error",
+                "noCatchAssign": "error",
+                "noClassAssign": "error",
+                "noCompareNegZero": "error",
+                "noConsole": "off",
+                "noControlCharactersInRegex": "error",
+                "noDebugger": "error",
+                "noDuplicateCase": "error",
+                "noDuplicateClassMembers": "error",
+                "noDuplicateObjectKeys": "error",
+                "noDuplicateParameters": "error",
+                "noEmptyBlockStatements": "error",
+                "noFallthroughSwitchClause": "error",
+                "noFunctionAssign": "error",
+                "noGlobalAssign": "error",
+                "noImportAssign": "error",
+                "noMisleadingCharacterClass": "error",
+                "noPrototypeBuiltins": "error",
+                "noRedeclare": "error",
+                "noShadowRestrictedNames": "error",
+                "noSparseArray": "error",
+                "noUnsafeNegation": "error",
+                "useGetterReturn": "error",
+                "useIsArray": "error",
+                "useValidTypeof": "error"
+            }
+        }
+    },
+    "javascript": {
+        "formatter": {
+            "jsxQuoteStyle": "double",
+            "quoteProperties": "asNeeded",
+            "trailingCommas": "all",
+            "semicolons": "always",
+            "arrowParentheses": "always",
+            "bracketSameLine": false,
+            "quoteStyle": "double",
+            "attributePosition": "auto",
+            "bracketSpacing": true
+        }
+    },
+    "overrides": [
+        {
+            "include": ["src/**/*.ts", "hak/**/*.ts", "scripts/**/*.ts", "playwright/**/*.ts"],
+            "linter": {
+                "rules": {
+                    "style": { "noNonNullAssertion": "off" },
+                    "suspicious": { "noExplicitAny": "off" }
+                }
+            }
+        },
+        {
+            "include": ["playwright/**/*.ts"],
+            "linter": {
+                "rules": {
+                    "correctness": {
+                        "noEmptyPattern": "off"
+                    }
+                }
+            }
+        }
+    ]
+}

electron-builder.ts

@@ -1,10 +1,10 @@
-import * as os from "node:os";
 import * as fs from "node:fs";
+import { readFile, writeFile } from "node:fs/promises";
+import * as os from "node:os";
 import * as path from "node:path";
-import * as plist from "plist";
-import { AfterPackContext, Arch, Configuration as BaseConfiguration, Platform } from "electron-builder";
 import { computeData } from "app-builder-lib/out/asar/integrity";
-import { readFile, writeFile } from "node:fs/promises";
+import { type AfterPackContext, Arch, type Configuration as BaseConfiguration, Platform } from "electron-builder";
+import * as plist from "plist";
 
 /**
  * This script has different outputs depending on your os platform.

hak/matrix-seshat/build.ts

@@ -6,8 +6,8 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Com
 Please see LICENSE files in the repository root for full details.
 */
 
-import type HakEnv from "../../scripts/hak/hakEnv.js";
 import type { DependencyInfo } from "../../scripts/hak/dep.js";
+import type HakEnv from "../../scripts/hak/hakEnv.js";
 
 export default async function (hakEnv: HakEnv, moduleInfo: DependencyInfo): Promise<void> {
     const env = hakEnv.makeGypEnv();

hak/matrix-seshat/check.ts

@@ -9,11 +9,11 @@ Please see LICENSE files in the repository root for full details.
 import childProcess from "node:child_process";
 import fsProm from "node:fs/promises";
 
+import type { DependencyInfo } from "../../scripts/hak/dep.js";
 import type HakEnv from "../../scripts/hak/hakEnv.js";
 import type { Tool } from "../../scripts/hak/hakEnv.js";
-import type { DependencyInfo } from "../../scripts/hak/dep.js";
 
-export default async function (hakEnv: HakEnv, moduleInfo: DependencyInfo): Promise<void> {
+export default async function (hakEnv: HakEnv, _moduleInfo: DependencyInfo): Promise<void> {
     const tools: Tool[] = [
         ["rustc", "--version"],
         ["python", "--version"], // node-gyp uses python for reasons beyond comprehension
@@ -33,7 +33,7 @@ export default async function (hakEnv: HakEnv, moduleInfo: DependencyInfo): Prom
         const rustc = childProcess.execFile(
             "rustc",
             ["--target", hakEnv.getTargetId(), "--emit=obj", "-o", "tmp", "-"],
-            (err, out) => {
+            (err) => {
                 if (err) {
                     reject(
                         "rustc can't build for target " +

knip.ts

@@ -1,4 +1,4 @@
-import { KnipConfig } from "knip";
+import type { KnipConfig } from "knip";
 
 export default {
     entry: ["src/electron-main.ts", "src/preload.ts", "electron-builder.ts", ".eslintrc-*.js", "scripts/**", "hak/**"],

package.json

@@ -20,15 +20,15 @@
     "scripts": {
         "i18n": "matrix-gen-i18n && yarn i18n:sort && yarn i18n:lint",
         "i18n:sort": "jq --sort-keys '.' src/i18n/strings/en_EN.json > src/i18n/strings/en_EN.json.tmp && mv src/i18n/strings/en_EN.json.tmp src/i18n/strings/en_EN.json",
-        "i18n:lint": "prettier --log-level=silent  --write src/i18n/strings/ --ignore-path /dev/null",
+        "i18n:lint": "biome format --log-level=none --write src/i18n/strings/",
         "i18n:diff": "cp src/i18n/strings/en_EN.json src/i18n/strings/en_EN_orig.json && yarn i18n && matrix-compare-i18n-files src/i18n/strings/en_EN_orig.json src/i18n/strings/en_EN.json",
         "mkdirs": "mkdirp packages deploys",
         "fetch": "yarn run mkdirs && tsx scripts/fetch-package.ts",
         "asar-webapp": "asar p webapp webapp.asar",
         "start": "yarn run build:ts && yarn run build:res && electron .",
         "lint": "yarn lint:types && yarn lint:js && yarn lint:workflows",
-        "lint:js": "eslint --max-warnings 0 src hak playwright scripts && prettier --check .",
-        "lint:js-fix": "eslint --fix --max-warnings 0 src hak playwright scripts && prettier --log-level=warn --write .",
+        "lint:js": "biome check",
+        "lint:js-fix": "biome check --write",
         "lint:types": "yarn lint:types:src && yarn lint:types:test && yarn lint:types:scripts && yarn lint:types:hak",
         "lint:types:src": "tsc --noEmit",
         "lint:types:test": "tsc --noEmit -p playwright/tsconfig.json",
@@ -74,30 +74,21 @@
         "@babel/core": "^7.18.10",
         "@babel/preset-env": "^7.18.10",
         "@babel/preset-typescript": "^7.18.6",
+        "@biomejs/biome": "^1.9.4",
         "@electron/asar": "3.3.1",
         "@playwright/test": "1.51.0",
-        "@stylistic/eslint-plugin": "^3.0.0",
         "@types/auto-launch": "^5.0.1",
         "@types/counterpart": "^0.18.1",
         "@types/minimist": "^1.2.1",
         "@types/node": "18.19.79",
         "@types/pacote": "^11.1.1",
-        "@typescript-eslint/eslint-plugin": "^8.0.0",
-        "@typescript-eslint/parser": "^8.0.0",
         "app-builder-lib": "26.0.11",
         "chokidar": "^4.0.0",
         "detect-libc": "^2.0.0",
         "electron": "34.3.1",
         "electron-builder": "26.0.11",
         "electron-builder-squirrel-windows": "26.0.11",
         "electron-devtools-installer": "^4.0.0",
-        "eslint": "^8.26.0",
-        "eslint-config-google": "^0.14.0",
-        "eslint-config-prettier": "^10.0.0",
-        "eslint-plugin-import": "^2.25.4",
-        "eslint-plugin-matrix-org": "^2.0.1",
-        "eslint-plugin-n": "^17.12.0",
-        "eslint-plugin-unicorn": "^56.0.0",
         "glob": "^11.0.0",
         "husky": "^9.1.6",
         "knip": "^5.0.0",
@@ -106,7 +97,6 @@
         "mkdirp": "^3.0.0",
         "pacote": "^21.0.0",
         "plist": "^3.1.0",
-        "prettier": "^3.0.0",
         "rimraf": "^6.0.0",
         "tar": "^7.0.0",
         "tsx": "^4.19.2",

playwright/e2e/launch/config-options.spec.ts

@@ -5,10 +5,10 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Com
 Please see LICENSE files in the repository root for full details.
 */
 
-import { resolve, dirname } from "node:path";
+import { dirname, resolve } from "node:path";
 import { fileURLToPath } from "node:url";
 
-import { test, expect } from "../../element-desktop-test.js";
+import { expect, test } from "../../element-desktop-test.js";
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 

playwright/e2e/launch/launch.spec.ts

@@ -8,7 +8,7 @@ Please see LICENSE files in the repository root for full details.
 
 import { platform } from "node:os";
 
-import { test, expect } from "../../element-desktop-test.js";
+import { expect, test } from "../../element-desktop-test.js";
 
 declare global {
     interface Window {
@@ -63,7 +63,7 @@ test.describe("App launch", () => {
 
         // XXX: this test works fine locally but in CI the app start races with the test plumbing up the stdout/stderr pipes
         // which means the logs are missed, disabling for now.
-        test.skip("should respect option", async ({ page, stdout }) => {
+        test.skip("should respect option", async ({ page: _page, stdout }) => {
             expect(stdout.data.toString()).toContain("Auto update disabled via command line flag");
         });
     });