Enable @typescript-eslint/no-redundant-type-constituents rule (#15794)

eslint.config.js

@@ -140,7 +140,6 @@ module.exports = [
           "@typescript-eslint/no-explicit-any": "off",
           "@typescript-eslint/no-misused-promises": "off",
           "@typescript-eslint/no-namespace": "off",
-          "@typescript-eslint/no-redundant-type-constituents": "off",
           "@typescript-eslint/no-this-alias": "off",
           "@typescript-eslint/no-unsafe-assignment": "off",
           "@typescript-eslint/no-unsafe-call": "off",

packages/babel-cli/src/babel-external-helpers.ts

@@ -1,10 +1,7 @@
 import commander from "commander";
 import { buildExternalHelpers } from "@babel/core";
 
-function collect(
-  value: string | any,
-  previousValue: Array<string>,
-): Array<string> {
+function collect(value: unknown, previousValue: Array<string>): Array<string> {
   // If the user passed the option with no value, like "babel-external-helpers --whitelist", do nothing.
   if (typeof value !== "string") return previousValue;
 

packages/babel-cli/src/babel/file.ts

@@ -9,6 +9,7 @@ import type { CmdOptions } from "./options";
 import * as watcher from "./watcher";
 
 import type {
+  EncodedSourceMap,
   SectionedSourceMap,
   SourceMapInput,
   TraceMap,
@@ -40,7 +41,7 @@ export default async function ({
 
       mapSections.push({
         offset: { line: offset, column: 0 },
-        map: result.map || {
+        map: (result.map as EncodedSourceMap) || {
           version: 3,
           names: [],
           sources: [],

packages/babel-cli/src/babel/options.ts

@@ -359,7 +359,9 @@ export default function parseArgv(args: Array<string>): CmdOptions | null {
   };
 }
 
-function booleanify(val: any): boolean | any {
+function booleanify(val: "false" | 0 | ""): false;
+function booleanify(val: "true" | 1): true;
+function booleanify(val: any): any {
   if (val === undefined) return undefined;
 
   if (val === "true" || val == 1) {
@@ -373,10 +375,7 @@ function booleanify(val: any): boolean | any {
   return val;
 }
 
-function collect(
-  value: string | any,
-  previousValue: Array<string>,
-): Array<string> {
+function collect(value: unknown, previousValue: Array<string>): Array<string> {
   // If the user passed the option with no value, like "babel file.js --presets", do nothing.
   if (typeof value !== "string") return previousValue;
 

packages/babel-core/src/config/config-chain.ts

@@ -18,6 +18,7 @@ import type { ReadonlyDeepArray } from "./helpers/deep-array";
 
 import { endHiddenCallStack } from "../errors/rewrite-stack-trace";
 import ConfigError from "../errors/config-error";
+import type { PluginAPI, PresetAPI } from "./helpers/config-api";
 
 const debug = buildDebug("babel:config:config-chain");
 
@@ -42,8 +43,8 @@ import type {
 } from "./config-descriptors";
 
 export type ConfigChain = {
-  plugins: Array<UnloadedDescriptor>;
-  presets: Array<UnloadedDescriptor>;
+  plugins: Array<UnloadedDescriptor<PluginAPI>>;
+  presets: Array<UnloadedDescriptor<PresetAPI>>;
   options: Array<ValidatedOptions>;
   files: Set<string>;
 };
@@ -760,12 +761,12 @@ function normalizeOptions(opts: ValidatedOptions): ValidatedOptions {
   return options;
 }
 
-function dedupDescriptors(
-  items: Array<UnloadedDescriptor>,
-): Array<UnloadedDescriptor> {
+function dedupDescriptors<API>(
+  items: Array<UnloadedDescriptor<API>>,
+): Array<UnloadedDescriptor<API>> {
   const map: Map<
     Function,
-    Map<string | void, { value: UnloadedDescriptor }>
+    Map<string | void, { value: UnloadedDescriptor<API> }>
   > = new Map();
 
   const descriptors = [];

packages/babel-core/src/config/config-descriptors.ts

@@ -19,35 +19,36 @@ import type {
 } from "./validation/options";
 
 import { resolveBrowserslistConfigFile } from "./resolve-targets";
+import type { PluginAPI, PresetAPI } from "./helpers/config-api";
 
 // Represents a config object and functions to lazily load the descriptors
 // for the plugins and presets so we don't load the plugins/presets unless
 // the options object actually ends up being applicable.
 export type OptionsAndDescriptors = {
   options: ValidatedOptions;
-  plugins: () => Handler<Array<UnloadedDescriptor>>;
-  presets: () => Handler<Array<UnloadedDescriptor>>;
+  plugins: () => Handler<Array<UnloadedDescriptor<PluginAPI>>>;
+  presets: () => Handler<Array<UnloadedDescriptor<PresetAPI>>>;
 };
 
 // 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 type UnloadedDescriptor = {
+export interface UnloadedDescriptor<API, Options = {} | undefined | false> {
   name: string | undefined;
-  value: any | Function;
-  options: {} | undefined | false;
+  value: object | ((api: API, options: Options, dirname: string) => unknown);
+  options: Options;
   dirname: string;
   alias: string;
   ownPass?: boolean;
   file?: {
     request: string;
     resolved: string;
   };
-};
+}
 
-function isEqualDescriptor(
-  a: UnloadedDescriptor,
-  b: UnloadedDescriptor,
+function isEqualDescriptor<API>(
+  a: UnloadedDescriptor<API>,
+  b: UnloadedDescriptor<API>,
 ): boolean {
   return (
     a.name === b.name &&
@@ -150,7 +151,7 @@ const createCachedPresetDescriptors = makeWeakCacheSync(
     return makeStrongCacheSync((alias: string) =>
       makeStrongCache(function* (
         passPerPreset: boolean,
-      ): Handler<Array<UnloadedDescriptor>> {
+      ): Handler<Array<UnloadedDescriptor<PresetAPI>>> {
         const descriptors = yield* createPresetDescriptors(
           items,
           dirname,
@@ -174,7 +175,7 @@ const createCachedPluginDescriptors = makeWeakCacheSync(
     const dirname = cache.using(dir => dir);
     return makeStrongCache(function* (
       alias: string,
-    ): Handler<Array<UnloadedDescriptor>> {
+    ): Handler<Array<UnloadedDescriptor<PluginAPI>>> {
       const descriptors = yield* createPluginDescriptors(items, dirname, alias);
       return descriptors.map(
         // Items are cached using the overall plugin array identity when
@@ -197,9 +198,9 @@ const DEFAULT_OPTIONS = {};
  * cache, or else returns the input descriptor and adds it to the cache for
  * next time.
  */
-function loadCachedDescriptor(
-  cache: WeakMap<{} | Function, WeakMap<{}, Array<UnloadedDescriptor>>>,
-  desc: UnloadedDescriptor,
+function loadCachedDescriptor<API>(
+  cache: WeakMap<{} | Function, WeakMap<{}, Array<UnloadedDescriptor<API>>>>,
+  desc: UnloadedDescriptor<API>,
 ) {
   const { value, options = DEFAULT_OPTIONS } = desc;
   if (options === false) return desc;
@@ -235,7 +236,7 @@ function* createPresetDescriptors(
   dirname: string,
   alias: string,
   passPerPreset: boolean,
-): Handler<Array<UnloadedDescriptor>> {
+): Handler<Array<UnloadedDescriptor<PresetAPI>>> {
   return yield* createDescriptors(
     "preset",
     items,
@@ -249,17 +250,17 @@ function* createPluginDescriptors(
   items: PluginList,
   dirname: string,
   alias: string,
-): Handler<Array<UnloadedDescriptor>> {
+): Handler<Array<UnloadedDescriptor<PluginAPI>>> {
   return yield* createDescriptors("plugin", items, dirname, alias);
 }
 
-function* createDescriptors(
+function* createDescriptors<API>(
   type: "plugin" | "preset",
   items: PluginList,
   dirname: string,
   alias: string,
   ownPass?: boolean,
-): Handler<Array<UnloadedDescriptor>> {
+): Handler<Array<UnloadedDescriptor<API>>> {
   const descriptors = yield* gensync.all(
     items.map((item, index) =>
       createDescriptor(item, dirname, {
@@ -278,7 +279,7 @@ function* createDescriptors(
 /**
  * Given a plugin/preset item, resolve it into a standard format.
  */
-export function* createDescriptor(
+export function* createDescriptor<API>(
   pair: PluginItem,
   dirname: string,
   {
@@ -290,7 +291,7 @@ export function* createDescriptor(
     alias: string;
     ownPass?: boolean;
   },
-): Handler<UnloadedDescriptor> {
+): Handler<UnloadedDescriptor<API>> {
   const desc = getItemDescriptor(pair);
   if (desc) {
     return desc;
@@ -365,7 +366,7 @@ export function* createDescriptor(
   };
 }
 
-function assertNoDuplicates(items: Array<UnloadedDescriptor>): void {
+function assertNoDuplicates<API>(items: Array<UnloadedDescriptor<API>>): void {
   const map = new Map();
 
   for (const item of items) {

packages/babel-core/src/config/full.ts

@@ -89,20 +89,22 @@ export default gensync(function* loadFullConfig(
 
   const presetsDescriptors = presets.map(toDescriptor);
   const initialPluginsDescriptors = plugins.map(toDescriptor);
-  const pluginDescriptorsByPass: Array<Array<UnloadedDescriptor>> = [[]];
+  const pluginDescriptorsByPass: Array<Array<UnloadedDescriptor<PluginAPI>>> = [
+    [],
+  ];
   const passes: Array<Array<Plugin>> = [];
 
   const externalDependencies: DeepArray<string> = [];
 
   const ignored = yield* enhanceError(
     context,
     function* recursePresetDescriptors(
-      rawPresets: Array<UnloadedDescriptor>,
-      pluginDescriptorsPass: Array<UnloadedDescriptor>,
+      rawPresets: Array<UnloadedDescriptor<PresetAPI>>,
+      pluginDescriptorsPass: Array<UnloadedDescriptor<PluginAPI>>,
     ): Handler<true | void> {
       const presets: Array<{
         preset: ConfigChain | null;
-        pass: Array<UnloadedDescriptor>;
+        pass: Array<UnloadedDescriptor<PluginAPI>>;
       }> = [];
 
       for (let i = 0; i < rawPresets.length; i++) {
@@ -178,7 +180,7 @@ export default gensync(function* loadFullConfig(
       passes.push(pass);
 
       for (let i = 0; i < descs.length; i++) {
-        const descriptor: UnloadedDescriptor = descs[i];
+        const descriptor = descs[i];
         if (descriptor.options !== false) {
           try {
             // eslint-disable-next-line no-var
@@ -240,7 +242,7 @@ const makeDescriptorLoader = <Context, API>(
   ) => API,
 ) =>
   makeWeakCache(function* (
-    { value, options, dirname, alias }: UnloadedDescriptor,
+    { value, options, dirname, alias }: UnloadedDescriptor<API>,
     cache: CacheConfigurator<Context>,
   ): Handler<LoadedDescriptor> {
     // Disabled presets should already have been filtered out
@@ -250,10 +252,10 @@ const makeDescriptorLoader = <Context, API>(
 
     const externalDependencies: Array<string> = [];
 
-    let item = value;
+    let item: unknown = value;
     if (typeof value === "function") {
       const factory = maybeAsync(
-        value,
+        value as (api: API, options: {}, dirname: string) => unknown,
         `You appear to be using an async plugin/preset, but Babel has been called synchronously`,
       );
 
@@ -344,7 +346,7 @@ const instantiatePlugin = makeWeakCache(function* (
   }
 
   if (plugin.inherits) {
-    const inheritsDescriptor: UnloadedDescriptor = {
+    const inheritsDescriptor: UnloadedDescriptor<PluginAPI> = {
       name: undefined,
       alias: `${alias}$inherits`,
       value: plugin.inherits,
@@ -387,7 +389,7 @@ const instantiatePlugin = makeWeakCache(function* (
  * Instantiate a plugin for the given descriptor, returning the plugin/options pair.
  */
 function* loadPluginDescriptor(
-  descriptor: UnloadedDescriptor,
+  descriptor: UnloadedDescriptor<PluginAPI>,
   context: Context.SimplePlugin,
 ): Handler<Plugin> {
   if (descriptor.value instanceof Plugin) {
@@ -410,7 +412,7 @@ const needsFilename = (val: unknown) => val && typeof val !== "function";
 
 const validateIfOptionNeedsFilename = (
   options: ValidatedOptions,
-  descriptor: UnloadedDescriptor,
+  descriptor: UnloadedDescriptor<PresetAPI>,
 ): void => {
   if (
     needsFilename(options.test) ||
@@ -435,7 +437,7 @@ const validateIfOptionNeedsFilename = (
 const validatePreset = (
   preset: PresetInstance,
   context: ConfigContext,
-  descriptor: UnloadedDescriptor,
+  descriptor: UnloadedDescriptor<PresetAPI>,
 ): void => {
   if (!context.filename) {
     const { options } = preset;
@@ -466,7 +468,7 @@ const instantiatePreset = makeWeakCacheSync(
  * Generate a config object that will act as the root of a new nested config.
  */
 function* loadPresetDescriptor(
-  descriptor: UnloadedDescriptor,
+  descriptor: UnloadedDescriptor<PresetAPI>,
   context: Context.FullPreset,
 ): Handler<{
   chain: ConfigChain | null;

packages/babel-core/src/config/index.ts

@@ -73,7 +73,7 @@ export const createConfigItemAsync = createConfigItemRunner.async;
 export function createConfigItem(
   target: PluginTarget,
   options: Parameters<typeof createConfigItemImpl>[1],
-  callback?: (err: Error, val: ConfigItem | null) => void,
+  callback?: (err: Error, val: ConfigItem<PluginAPI> | null) => void,
 ) {
   if (callback !== undefined) {
     createConfigItemRunner.errback(target, options, callback);