Add explicit .ts/.js extension to all imports in src

Gulpfile.mjs

@@ -182,7 +182,7 @@ function generateStandalone() {
       through.obj(async (file, enc, callback) => {
         log("Generating @babel/standalone files");
         const pluginConfig = JSON.parse(file.contents);
-        let imports = `import makeNoopPlugin from "../make-noop-plugin";`;
+        let imports = `import makeNoopPlugin from "../make-noop-plugin.ts";`;
         let exportDecls = "";
         let exportsList = "";
         let allList = "";

babel.config.js

@@ -77,8 +77,7 @@ module.exports = function (api) {
 
   let targets = {};
   let convertESM = outputType === "script";
-  /** @type {false | "externals" | "always"} */
-  let addImportExtension = convertESM ? false : "always";
+  let replaceTSImportExtension = true;
   let ignoreLib = true;
   let includeRegeneratorRuntime = false;
   let needsPolyfillsForOldNode = false;
@@ -107,7 +106,7 @@ module.exports = function (api) {
     case "standalone":
       includeRegeneratorRuntime = true;
       convertESM = false;
-      addImportExtension = false;
+      replaceTSImportExtension = false;
       ignoreLib = false;
       // rollup-commonjs will converts node_modules to ESM
       unambiguousSources.push(
@@ -120,7 +119,7 @@ module.exports = function (api) {
       break;
     case "rollup":
       convertESM = false;
-      addImportExtension = "externals";
+      replaceTSImportExtension = false;
       ignoreLib = false;
       // rollup-commonjs will converts node_modules to ESM
       unambiguousSources.push(
@@ -230,9 +229,7 @@ module.exports = function (api) {
         assumptions: sourceAssumptions,
         plugins: [
           transformNamedBabelTypesImportToDestructuring,
-          addImportExtension
-            ? [pluginAddImportExtension, { when: addImportExtension }]
-            : null,
+          replaceTSImportExtension ? pluginReplaceTSImportExtension : null,
 
           [
             pluginToggleBooleanFlag,
@@ -787,56 +784,13 @@ function pluginImportMetaUrl({ types: t, template }) {
   };
 }
 
-function pluginAddImportExtension(api, { when }) {
+function pluginReplaceTSImportExtension() {
   return {
     visitor: {
       "ImportDeclaration|ExportDeclaration"({ node }) {
         const { source } = node;
-        if (!source) return;
-
-        if (
-          when === "always" &&
-          source.value.startsWith(".") &&
-          !/\.[a-z]+$/.test(source.value)
-        ) {
-          const dir = pathUtils.dirname(this.filename);
-
-          try {
-            const pkg = JSON.parse(
-              fs.readFileSync(
-                pathUtils.join(dir, `${source.value}/package.json`)
-              ),
-              "utf8"
-            );
-
-            if (pkg.main) source.value = pathUtils.join(source.value, pkg.main);
-          } catch (_) {}
-
-          try {
-            if (fs.statSync(pathUtils.join(dir, source.value)).isFile()) return;
-          } catch (_) {}
-
-          for (const [src, lib = src] of [["ts", "js"], ["js"], ["cjs"]]) {
-            try {
-              fs.statSync(pathUtils.join(dir, `${source.value}.${src}`));
-              source.value += `.${lib}`;
-              return;
-            } catch (_) {}
-          }
-
-          source.value += "/index.js";
-        }
-        if (
-          source.value.startsWith("lodash/") ||
-          source.value.startsWith("core-js-compat/") ||
-          source.value === "core-js/stable/index" ||
-          source.value === "regenerator-runtime/runtime" ||
-          source.value === "babel-plugin-dynamic-import-node/utils"
-        ) {
-          source.value += ".js";
-        }
-        if (source.value.startsWith("@babel/preset-modules/")) {
-          source.value += "/index.js";
+        if (source) {
+          source.value = source.value.replace(/(\.[mc]?)ts$/, "$1js");
         }
       },
     },

eslint.config.js

@@ -173,7 +173,7 @@ module.exports = [
       "@babel/development/no-undefined-identifier": "error",
       "@babel/development/no-deprecated-clone": "error",
       "guard-for-in": "error",
-      "import/extensions": ["error", { json: "always", cjs: "always" }],
+      "import/extensions": ["error", "ignorePackages"],
     },
   },
   ...compat.extends("plugin:jest/recommended").map(config => {

lib/third-party-libs.d.ts

@@ -1,67 +1,69 @@
+/* eslint-disable import/no-extraneous-dependencies */
+
 declare module "js-tokens" {
   // TODO(Babel 8): Remove this
   export { default } from "js-tokens-BABEL_8_BREAKING-true";
   export * from "js-tokens-BABEL_8_BREAKING-true";
 }
 
-declare module "@babel/preset-modules/lib/plugins/transform-async-arrows-in-class" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-async-arrows-in-class/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
-declare module "@babel/preset-modules/lib/plugins/transform-edge-default-parameters" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-edge-default-parameters/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
-declare module "@babel/preset-modules/lib/plugins/transform-edge-function-name" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-edge-function-name/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
-declare module "@babel/preset-modules/lib/plugins/transform-tagged-template-caching" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-tagged-template-caching/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
-declare module "@babel/preset-modules/lib/plugins/transform-safari-block-shadowing" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-safari-block-shadowing/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
-declare module "@babel/preset-modules/lib/plugins/transform-safari-for-shadowing" {
-  import { declare } from "@babel/helper-plugin-utils";
+declare module "@babel/preset-modules/lib/plugins/transform-safari-for-shadowing/index.js" {
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
 declare module "babel-plugin-polyfill-corejs2" {
-  import { declare } from "@babel/helper-plugin-utils";
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
 declare module "babel-plugin-polyfill-corejs3" {
-  import { declare } from "@babel/helper-plugin-utils";
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
 declare module "babel-plugin-polyfill-regenerator" {
-  import { declare } from "@babel/helper-plugin-utils";
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }
 
 declare module "regenerator-transform" {
-  import { declare } from "@babel/helper-plugin-utils";
+  import type { declare } from "@babel/helper-plugin-utils";
   let plugin: ReturnType<typeof declare>;
-  let exports: {default: typeof plugin};
+  let exports: { default: typeof plugin };
   export = exports;
 }

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

@@ -2,9 +2,9 @@ import slash from "slash";
 import path from "path";
 import fs from "fs";
 
-import * as util from "./util";
-import * as watcher from "./watcher";
-import type { CmdOptions } from "./options";
+import * as util from "./util.ts";
+import * as watcher from "./watcher.ts";
+import type { CmdOptions } from "./options.ts";
 
 const FILE_TYPE = Object.freeze({
   NON_COMPILABLE: "NON_COMPILABLE",

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

@@ -4,9 +4,9 @@ import slash from "slash";
 import path from "path";
 import fs from "fs";
 
-import * as util from "./util";
-import type { CmdOptions } from "./options";
-import * as watcher from "./watcher";
+import * as util from "./util.ts";
+import type { CmdOptions } from "./options.ts";
+import * as watcher from "./watcher.ts";
 
 import type {
   EncodedSourceMap,

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

@@ -1,8 +1,8 @@
 #!/usr/bin/env node
 
-import parseArgv from "./options";
-import dirCommand from "./dir";
-import fileCommand from "./file";
+import parseArgv from "./options.ts";
+import dirCommand from "./dir.ts";
+import fileCommand from "./file.ts";
 
 const opts = parseArgv(process.argv);
 

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

@@ -3,7 +3,7 @@ import * as babel from "@babel/core";
 import path from "path";
 import fs from "fs";
 
-import * as watcher from "./watcher";
+import * as watcher from "./watcher.ts";
 
 import type { FileResult, InputOptions } from "@babel/core";
 

packages/babel-core/src/config/cache-contexts.ts

@@ -1,7 +1,7 @@
 import type { Targets } from "@babel/helper-compilation-targets";
 
-import type { ConfigContext } from "./config-chain";
-import type { CallerMetadata } from "./validation/options";
+import type { ConfigContext } from "./config-chain.ts";
+import type { CallerMetadata } from "./validation/options.ts";
 
 export type { ConfigContext as FullConfig };
 

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

@@ -6,8 +6,8 @@ import {
   onFirstPause,
   waitFor,
   isThenable,
-} from "../gensync-utils/async";
-import { isIterableIterator } from "./util";
+} from "../gensync-utils/async.ts";
+import { isIterableIterator } from "./util.ts";
 
 export type { CacheConfigurator };
 

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

@@ -3,22 +3,22 @@
 import path from "path";
 import buildDebug from "debug";
 import type { Handler } from "gensync";
-import { validate } from "./validation/options";
+import { validate } from "./validation/options.ts";
 import type {
   ValidatedOptions,
   IgnoreList,
   ConfigApplicableTest,
   BabelrcSearch,
   CallerMetadata,
   IgnoreItem,
-} from "./validation/options";
-import pathPatternToRegex from "./pattern-to-regex";
-import { ConfigPrinter, ChainFormatter } from "./printer";
-import type { ReadonlyDeepArray } from "./helpers/deep-array";
+} from "./validation/options.ts";
+import pathPatternToRegex from "./pattern-to-regex.ts";
+import { ConfigPrinter, ChainFormatter } from "./printer.ts";
+import type { ReadonlyDeepArray } from "./helpers/deep-array.ts";
 
-import { endHiddenCallStack } from "../errors/rewrite-stack-trace";
-import ConfigError from "../errors/config-error";
-import type { PluginAPI, PresetAPI } from "./helpers/config-api";
+import { endHiddenCallStack } from "../errors/rewrite-stack-trace.ts";
+import ConfigError from "../errors/config-error.ts";
+import type { PluginAPI, PresetAPI } from "./helpers/config-api.ts";
 
 const debug = buildDebug("babel:config:config-chain");
 
@@ -27,20 +27,20 @@ import {
   findRelativeConfig,
   findRootConfig,
   loadConfig,
-} from "./files";
-import type { ConfigFile, IgnoreFile, FilePackageData } from "./files";
+} from "./files/index.ts";
+import type { ConfigFile, IgnoreFile, FilePackageData } from "./files/index.ts";
 
-import { makeWeakCacheSync, makeStrongCacheSync } from "./caching";
+import { makeWeakCacheSync, makeStrongCacheSync } from "./caching.ts";
 
 import {
   createCachedDescriptors,
   createUncachedDescriptors,
-} from "./config-descriptors";
+} from "./config-descriptors.ts";
 import type {
   UnloadedDescriptor,
   OptionsAndDescriptors,
   ValidatedFile,
-} from "./config-descriptors";
+} from "./config-descriptors.ts";
 
 export type ConfigChain = {
   plugins: Array<UnloadedDescriptor<PluginAPI>>;

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

@@ -1,25 +1,25 @@
 import gensync, { type Handler } from "gensync";
-import { once } from "../gensync-utils/functional";
+import { once } from "../gensync-utils/functional.ts";
 
-import { loadPlugin, loadPreset } from "./files";
+import { loadPlugin, loadPreset } from "./files/index.ts";
 
-import { getItemDescriptor } from "./item";
+import { getItemDescriptor } from "./item.ts";
 
 import {
   makeWeakCacheSync,
   makeStrongCacheSync,
   makeStrongCache,
-} from "./caching";
-import type { CacheConfigurator } from "./caching";
+} from "./caching.ts";
+import type { CacheConfigurator } from "./caching.ts";
 
 import type {
   ValidatedOptions,
   PluginList,
   PluginItem,
-} from "./validation/options";
+} from "./validation/options.ts";
 
-import { resolveBrowserslistConfigFile } from "./resolve-targets";
-import type { PluginAPI, PresetAPI } from "./helpers/config-api";
+import { resolveBrowserslistConfigFile } from "./resolve-targets.ts";
+import type { PluginAPI, PresetAPI } from "./helpers/config-api.ts";
 
 // 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