Fixes fetcher with typescript safe imports via configs

.changeset/fair-flowers-sing.md

@@ -0,0 +1,5 @@
+---
+'@hypermod/cli': patch
+---
+
+Patches selection of transform via local config prompt

.changeset/spotty-parrots-move.md

@@ -0,0 +1,5 @@
+---
+'@hypermod/fetcher': minor
+---
+
+Adds typescript support for config requires. Now a config can be in TS/TSX etc.

packages/cli/src/main.ts

@@ -164,9 +164,11 @@ export default async function main(
       if (config.transforms && config.transforms[answers.codemod]) {
         Object.entries(config.transforms)
           .filter(([key]) => semver.satisfies(key, `>=${answers.codemod}`))
-          .forEach(([, path]) => transforms.push(path));
+          .forEach(([, codemod]) =>
+            transforms.push(`${configFilePath}@${codemod}`),
+          );
       } else if (config.presets && config.presets[answers.codemod]) {
-        transforms.push(config.presets[answers.codemod]);
+        transforms.push(`${configFilePath}#${answers.codemod}`);
       }
     }
   }

packages/fetcher/package.json

@@ -7,7 +7,17 @@
   "license": "MIT",
   "repository": "https://github.com/hypermod-io/hypermod-community/tree/main/packages/fetcher",
   "dependencies": {
+    "@babel/core": "^7.13.16",
+    "@babel/parser": "^7.13.16",
+    "@babel/plugin-proposal-class-properties": "^7.13.0",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.13.8",
+    "@babel/plugin-proposal-optional-chaining": "^7.13.12",
+    "@babel/plugin-transform-modules-commonjs": "^7.13.8",
+    "@babel/preset-flow": "^7.13.13",
+    "@babel/preset-typescript": "^7.13.16",
+    "@babel/register": "^7.13.16",
     "@hypermod/types": "*",
+    "babel-core": "^7.0.0-bridge.0",
     "chalk": "^4.1.0",
     "fs-extra": "^9.1.0",
     "globby": "^11.1.0",

packages/fetcher/src/index.ts

@@ -1,10 +1,44 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
 import fs from 'fs';
 import path from 'path';
 import globby from 'globby';
 import { PluginManager } from 'live-plugin-manager';
 
 import { Config } from '@hypermod/types';
 
+// This configuration allows us to require TypeScript config files directly
+const { DEFAULT_EXTENSIONS } = require('@babel/core');
+const presets = [];
+
+let presetEnv;
+try {
+  presetEnv = require('@babel/preset-env');
+  presets.push([presetEnv.default, { targets: { node: true } }]);
+} catch (_) {}
+
+require('@babel/register')({
+  configFile: false,
+  babelrc: false,
+  presets: [...presets, require('@babel/preset-typescript').default],
+  plugins: [
+    require('@babel/plugin-transform-class-properties').default,
+    require('@babel/plugin-transform-nullish-coalescing-operator').default,
+    require('@babel/plugin-transform-optional-chaining').default,
+    require('@babel/plugin-transform-modules-commonjs').default,
+    require('@babel/plugin-transform-private-methods').default,
+  ],
+  extensions: [...DEFAULT_EXTENSIONS, '.ts', '.tsx'],
+  // By default, babel register only compiles things inside the current working directory.
+  // https://github.com/babel/babel/blob/2a4f16236656178e84b05b8915aab9261c55782c/packages/babel-register/src/node.js#L140-L157
+  ignore: [
+    // Ignore parser related files
+    /@babel\/parser/,
+    /\/flow-parser\//,
+    /\/recast\//,
+    /\/ast-types\//,
+  ],
+});
+
 export interface ConfigMeta {
   filePath: string;
   config: Config;