babel · nicolo-ribaudo · Jun 19, 2024 · Jun 5, 2024 · Jun 5, 2024 · Jun 5, 2024
diff --git a/eslint.config.mjs b/eslint.config.mjs
@@ -88,18 +88,20 @@ export default [
       parser: typescriptEslint.parser,
       parserOptions: {
         allowAutomaticSingleRunInference: true,
-        // @ts-expect-error types are old
-        EXPERIMENTAL_useProjectService: {
-          maximumDefaultProjectFileMatchCount_THIS_WILL_SLOW_DOWN_LINTING: 1000,
-        },
+        projectService: true,
       },
     },
     plugins: {
       "@typescript-eslint": typescriptEslint.plugin,
     },
     rules: {
       "no-unused-vars": "off",
-      "@typescript-eslint/no-unused-vars": "error",
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        {
+          caughtErrorsIgnorePattern: "^_",
+        },
+      ],
       "no-dupe-class-members": "off",
       "@typescript-eslint/no-dupe-class-members": "error",
       "no-undef": "off",
@@ -165,6 +167,9 @@ export default [
       "@typescript-eslint/no-inferrable-types": "off",
       "@typescript-eslint/no-unsafe-argument": "off",
       "@typescript-eslint/no-unsafe-return": "off",
+
+      // v8
+      "@typescript-eslint/no-require-imports": "off",
     },
   }),
   {

diff --git a/package.json b/package.json
@@ -82,7 +82,7 @@
     "shelljs": "^0.8.5",
     "test262-stream": "^1.4.0",
     "typescript": "5.5.1-rc",
-    "typescript-eslint": "^7.8.0"
+    "typescript-eslint": "rc-v8"
   },
   "workspaces": [
     "codemods/*",

diff --git a/packages/babel-cli/src/babel/util.ts b/packages/babel-cli/src/babel/util.ts
@@ -10,7 +10,7 @@ import type { FileResult, InputOptions } from "@babel/core";
 export function chmod(src: string, dest: string): void {
   try {
     fs.chmodSync(dest, fs.statSync(src).mode);
-  } catch (err) {
+  } catch (_) {
-  } catch (_) {
+  } catch {
-  } catch (_) {
+  } catch {
     console.warn(`Cannot change permissions of ${dest}`);
   }
 }

diff --git a/packages/babel-core/src/config/config-chain.ts b/packages/babel-core/src/config/config-chain.ts
@@ -301,7 +301,7 @@ function babelrcLoadEnabled(
   // Fast path to avoid having to match patterns if the babelrc is just
   // loading in the standard root directory.
   if (babelrcRoots === undefined) {
-    return pkgData.directories.indexOf(absoluteRoot) !== -1;
+    return pkgData.directories.includes(absoluteRoot);
   }
 
   let babelrcPatterns = babelrcRoots;
@@ -317,7 +317,7 @@ function babelrcLoadEnabled(
   // Fast path to avoid having to match patterns if the babelrc is just
   // loading in the standard root directory.
   if (babelrcPatterns.length === 1 && babelrcPatterns[0] === absoluteRoot) {
-    return pkgData.directories.indexOf(absoluteRoot) !== -1;
+    return pkgData.directories.includes(absoluteRoot);
   }
 
   return babelrcPatterns.some(pat => {

diff --git a/packages/babel-core/src/config/config-descriptors.ts b/packages/babel-core/src/config/config-descriptors.ts
@@ -33,7 +33,7 @@ export type OptionsAndDescriptors = {
 // Represents a plugin or presets at a given location in a config object.
 // At this point these have been resolved to a specific object or function,
 // but have not yet been executed to call functions with options.
-export interface UnloadedDescriptor<API, Options = {} | undefined | false> {
+export interface UnloadedDescriptor<API, Options = object | undefined | false> {
   name: string | undefined;
   value: object | ((api: API, options: Options, dirname: string) => unknown);
   options: Options;
@@ -199,7 +199,10 @@ const DEFAULT_OPTIONS = {};
  * next time.
  */
 function loadCachedDescriptor<API>(
-  cache: WeakMap<{} | Function, WeakMap<{}, Array<UnloadedDescriptor<API>>>>,
+  cache: WeakMap<
+    object | Function,
+    WeakMap<object, Array<UnloadedDescriptor<API>>>
+  >,
   desc: UnloadedDescriptor<API>,
 ) {
   const { value, options = DEFAULT_OPTIONS } = desc;
@@ -217,7 +220,7 @@ function loadCachedDescriptor<API>(
     cacheByOptions.set(options, possibilities);
   }
 
-  if (possibilities.indexOf(desc) === -1) {
+  if (!possibilities.includes(desc)) {
     const matches = possibilities.filter(possibility =>
       isEqualDescriptor(possibility, desc),
     );

diff --git a/packages/babel-core/src/config/files/configuration.ts b/packages/babel-core/src/config/files/configuration.ts
@@ -57,7 +57,7 @@ const runConfig = makeWeakCache(function* runConfig(
   yield* [];
 
   return {
-    options: endHiddenCallStack(options as any as (api: ConfigAPI) => {})(
+    options: endHiddenCallStack(options as any as (api: ConfigAPI) => unknown)(
       makeConfigAPI(cache),
     ),
     cacheNeedsConfiguration: !cache.configured(),

diff --git a/packages/babel-core/src/config/full.ts b/packages/babel-core/src/config/full.ts
@@ -37,8 +37,8 @@ import type * as Context from "./cache-contexts.ts";
 import ConfigError from "../errors/config-error.ts";
 
 type LoadedDescriptor = {
-  value: {};
-  options: {};
+  value: any;
+  options: object;
   dirname: string;
   alias: string;
   externalDependencies: ReadonlyDeepArray<string>;
@@ -259,7 +259,7 @@ const makeDescriptorLoader = <Context, API>(
     let item: unknown = value;
     if (typeof value === "function") {
       const factory = maybeAsync(
-        value as (api: API, options: {}, dirname: string) => unknown,
+        value as (api: API, options: object, dirname: string) => unknown,
         `You appear to be using an async plugin/preset, but Babel has been called synchronously`,
       );
 

diff --git a/packages/babel-core/src/config/item.ts b/packages/babel-core/src/config/item.ts
@@ -77,15 +77,15 @@ class ConfigItem<API> {
   /**
    * The resolved value of the item itself.
    */
-  value: {} | Function;
+  value: object | Function;
 
   /**
    * The options, if any, that were passed to the item.
    * Mutating this will lead to undefined behavior.
    *
    * "false" means that this item has been disabled.
    */
-  options: {} | void | false;
+  options: object | void | false;
 
   /**
    * The directory that the options for this item are relative to.

diff --git a/packages/babel-core/src/config/plugin.ts b/packages/babel-core/src/config/plugin.ts
@@ -12,13 +12,13 @@ export default class Plugin {
   parserOverride?: Function;
   generatorOverride?: Function;
 
-  options: {};
+  options: object;
 
   externalDependencies: ReadonlyDeepArray<string>;
 
   constructor(
     plugin: PluginObject,
-    options: {},
+    options: object,
     key?: string,
     externalDependencies: ReadonlyDeepArray<string> = finalize([]),
   ) {

diff --git a/packages/babel-core/src/config/util.ts b/packages/babel-core/src/config/util.ts
@@ -24,7 +24,7 @@ export function mergeOptions(
   }
 }
 
-function mergeDefaultFields<T extends {}>(target: T, source: T) {
+function mergeDefaultFields<T extends object>(target: T, source: T) {
   for (const k of Object.keys(source) as (keyof T)[]) {
     const val = source[k];
     if (val !== undefined) target[k] = val;

diff --git a/packages/babel-core/src/config/validation/option-assertions.ts b/packages/babel-core/src/config/validation/option-assertions.ts
@@ -175,15 +175,15 @@ export function assertCallerMetadata(
 export function assertInputSourceMap(
   loc: OptionPath,
   value: unknown,
-): RootInputSourceMapOption | void {
+): RootInputSourceMapOption {
   if (
     value !== undefined &&
     typeof value !== "boolean" &&
     (typeof value !== "object" || !value)
   ) {
     throw new Error(`${msg(loc)} must be a boolean, object, or undefined`);
   }
-  return value;
+  return value as RootInputSourceMapOption;
 }
 
 export function assertString(loc: GeneralPath, value: unknown): string | void {

diff --git a/packages/babel-core/src/config/validation/options.ts b/packages/babel-core/src/config/validation/options.ts
@@ -233,7 +233,7 @@ export type BabelrcSearch = boolean | IgnoreItem | IgnoreList;
 export type SourceMapsOption = boolean | "inline" | "both";
 export type SourceTypeOption = "module" | "script" | "unambiguous";
 export type CompactOption = boolean | "auto";
-export type RootInputSourceMapOption = {} | boolean;
+export type RootInputSourceMapOption = object | boolean;
 export type RootMode = "root" | "upward" | "upward-optional";
 
 export type TargetsListOrObject =
@@ -302,7 +302,7 @@ function getSource(loc: NestingPath): OptionsSource {
 
 export function validate(
   type: OptionsSource,
-  opts: {},
+  opts: any,
   filename?: string,
 ): ValidatedOptions {
   try {
@@ -397,7 +397,7 @@ function throwUnknownError(loc: OptionPath) {
   }
 }
 
-function assertNoDuplicateSourcemap(opts: {}): void {
+function assertNoDuplicateSourcemap(opts: any): void {
   if (Object.hasOwn(opts, "sourceMap") && Object.hasOwn(opts, "sourceMaps")) {
     throw new Error(".sourceMap is an alias for .sourceMaps, cannot use both");
   }

diff --git a/packages/babel-core/src/index.ts b/packages/babel-core/src/index.ts
@@ -97,7 +97,7 @@ if (!process.env.BABEL_8_BREAKING && !USE_ESM) {
   // For easier backward-compatibility, provide an API like the one we exposed in Babel 6.
   // eslint-disable-next-line no-restricted-globals
   exports.OptionManager = class OptionManager {
-    init(opts: {}) {
+    init(opts: unknown) {
       return loadOptionsSync(opts);
     }
   };

diff --git a/packages/babel-core/src/tools/build-external-helpers.ts b/packages/babel-core/src/tools/build-external-helpers.ts
@@ -169,7 +169,7 @@ function buildHelpers(
 
   const refs: { [key: string]: t.Identifier | t.MemberExpression } = {};
   helpers.list.forEach(function (name) {
-    if (allowlist && allowlist.indexOf(name) < 0) return;
+    if (allowlist && !allowlist.includes(name)) return;
 
     const ref = (refs[name] = getHelperReference(name));
 

diff --git a/packages/babel-core/src/transformation/file/file.ts b/packages/babel-core/src/transformation/file/file.ts
@@ -39,7 +39,7 @@ export default class File {
     buildError: this.buildCodeFrameError.bind(this),
   };
 
-  constructor(options: {}, { code, ast, inputMap }: NormalizedFile) {
+  constructor(options: any, { code, ast, inputMap }: NormalizedFile) {
     this.opts = options;
     this.code = code;
     this.ast = ast;

diff --git a/packages/babel-core/src/transformation/normalize-opts.ts b/packages/babel-core/src/transformation/normalize-opts.ts
@@ -1,7 +1,7 @@
 import path from "path";
 import type { ResolvedConfig } from "../config/index.ts";
 
-export default function normalizeOptions(config: ResolvedConfig): {} {
+export default function normalizeOptions(config: ResolvedConfig) {
   const {
     filename,
     cwd,

diff --git a/packages/babel-core/src/transformation/plugin-pass.ts b/packages/babel-core/src/transformation/plugin-pass.ts
@@ -1,7 +1,7 @@
 import type * as t from "@babel/types";
 import type File from "./file/file.ts";
 
-export default class PluginPass<Options = {}> {
+export default class PluginPass<Options = object> {
   _map: Map<unknown, unknown> = new Map();
   key: string | undefined | null;
   file: File;

diff --git a/packages/babel-generator/src/buffer.ts b/packages/babel-generator/src/buffer.ts
@@ -265,6 +265,7 @@ export default class Buffer {
     this._last = str.charCodeAt(len - 1);
 
     if (++this._appendCount > 4096) {
+      // eslint-disable-next-line @typescript-eslint/no-unused-expressions
       +this._str; // Unexplainable huge performance boost. Ref: https://github.com/davidmarkclements/flatstr License: MIT
       this._buf += this._str;
       this._str = str;

diff --git a/packages/babel-generator/src/printer.ts b/packages/babel-generator/src/printer.ts
@@ -1247,6 +1247,7 @@ if (!process.env.BABEL_8_BREAKING) {
 }
 
 type GeneratorFunctions = typeof generatorFunctions;
+// eslint-disable-next-line @typescript-eslint/no-empty-object-type
 interface Printer extends GeneratorFunctions {}
 export default Printer;
 

diff --git a/packages/babel-helper-compilation-targets/src/index.ts b/packages/babel-helper-compilation-targets/src/index.ts
@@ -101,7 +101,7 @@ function getLowestVersions(browsers: Array<string>): Targets {
 
           all[target] = semverMin(version, parsedBrowserVersion);
         }
-      } catch (e) {}
+      } catch (_) {}
 
       return all;
     },
@@ -129,7 +129,7 @@ getting parsed as 6.1, which can lead to unexpected behavior.
 function semverifyTarget(target: Target, value: string) {
   try {
     return semverify(value);
-  } catch (error) {
+  } catch (_) {
     throw new Error(
       v.formatMessage(
         `'${value}' is not a valid value for 'targets.${target}'.`,

diff --git a/packages/babel-helper-create-class-features-plugin/src/decorators.ts b/packages/babel-helper-create-class-features-plugin/src/decorators.ts
@@ -915,6 +915,7 @@ function usesPrivateField(expression: t.Node) {
     t.traverseFast(expression, node => {
       if (t.isPrivateName(node)) {
         // TODO: Add early return support to t.traverseFast
+        // eslint-disable-next-line @typescript-eslint/only-throw-error
         throw null;
       }
     });
@@ -1077,6 +1078,7 @@ function transformClass(
           (t.isMetaProperty(node) && node.meta.name !== "import")
         ) {
           // TODO: Add early return support to t.traverseFast
+          // eslint-disable-next-line @typescript-eslint/only-throw-error
           throw null;
         }
       });

diff --git a/packages/babel-helper-create-class-features-plugin/src/fields.ts b/packages/babel-helper-create-class-features-plugin/src/fields.ts
@@ -1574,7 +1574,9 @@ export function buildFieldsInitNodes(
   ref ??= t.cloneNode(innerBindingRef);
 
   for (const prop of props) {
-    prop.isClassProperty() && ts.assertFieldTransformed(prop);
+    if (prop.isClassProperty()) {
+      ts.assertFieldTransformed(prop);
+    }
 
     // @ts-expect-error: TS doesn't infer that prop.node is not a StaticBlock
     const isStatic = !t.isStaticBlock?.(prop.node) && prop.node.static;

diff --git a/packages/babel-helper-fixtures/src/index.ts b/packages/babel-helper-fixtures/src/index.ts
@@ -71,7 +71,7 @@ type Suite = {
 function tryResolve(module: string) {
   try {
     return require.resolve(module);
-  } catch (e) {
+  } catch (_) {
     return null;
   }
 }
@@ -82,7 +82,7 @@ function assertDirectory(loc: string) {
 }
 
 function shouldIgnore(name: string, ignore?: Array<string>) {
-  if (ignore && ignore.indexOf(name) >= 0) {
+  if (ignore?.includes(name)) {
     return true;
   }
 
@@ -185,7 +185,7 @@ function pushTask(
     stderrLoc = taskDir + "/stderr.txt";
   } else if (taskDirStats.isFile()) {
     const ext = path.extname(taskDir);
-    if (EXTENSIONS.indexOf(ext) === -1) return;
+    if (!EXTENSIONS.includes(ext)) return;
 
     execLoc = taskDir;
     execLocAlias = suiteName + "/" + taskName;
@@ -386,7 +386,7 @@ function wrapPackagesArray(
       val[0] = path.resolve(optionsDir, val[0]);
     } else {
       let name = val[0];
-      const match = name.match(/^(@babel\/(?:plugin-|preset-)?)(.*)$/);
+      const match = /^(@babel\/(?:plugin-|preset-)?)(.*)$/.exec(name);
       if (match) {
         name = match[2];
       }
@@ -419,12 +419,12 @@ function wrapPackagesArray(
  * @export
  * @param {{}} options the imported options.json
  * @param {string} optionsDir the directory where options.json is placed
- * @returns {{}} options whose plugins/presets are resolved
+ * @returns {any} options whose plugins/presets are resolved
  */
 export function resolveOptionPluginOrPreset(
   options: any,
   optionsDir: string,
-): {} {
+): any {
   if (options.overrides) {
     for (const subOption of options.overrides) {
       resolveOptionPluginOrPreset(subOption, optionsDir);

diff --git a/packages/babel-helper-member-expression-to-functions/src/index.ts b/packages/babel-helper-member-expression-to-functions/src/index.ts
@@ -588,7 +588,7 @@ export interface Handler<State> {
   delete(this: HandlerState<State> & State, member: Member): t.Expression;
 }
 
-export interface HandlerState<State = {}> extends Handler<State> {
+export interface HandlerState<State = object> extends Handler<State> {
   handle(
     this: HandlerState<State> & State,
     member: Member,
@@ -604,7 +604,7 @@ export interface HandlerState<State = {}> extends Handler<State> {
 // get, set, and call methods.
 // Optionally, a memoise method may be defined on the state, which will be
 // called when the member is a self-referential update.
-export default function memberExpressionToFunctions<CustomState = {}>(
+export default function memberExpressionToFunctions<CustomState extends object>(
   path: NodePath,
   visitor: Visitor<HandlerState<CustomState>>,
   state: Handler<CustomState> & CustomState,