Use esbuild instead of babel for tests (#49)

Author: calebeby

babel.config.cjs

@@ -1,19 +1,6 @@
 module.exports = (api) => {
-  const isTest = api.env('test');
-
   const isRollup = api.caller((c) => c && c.name === '@rollup/plugin-babel');
 
-  if (isTest)
-    return {
-      plugins: [
-        '@babel/transform-modules-commonjs',
-        // TODO: remove when node 12 is dropped
-        '@babel/plugin-proposal-optional-chaining',
-      ],
-      // not using preset-env here because it slows down the tests a lot
-      presets: ['@babel/preset-typescript'],
-    };
-
   return {
     presets: [
       [

jest.config.js

@@ -4,4 +4,7 @@ module.exports = {
     'test-mule': '<rootDir>/dist/cjs/index.cjs',
   },
   testRunner: 'jest-circus/runner',
+  transform: {
+    '^.+\\.tsx?$': ['esbuild-jest', { sourcemap: true }],
+  },
 };

package-lock.json

@@ -25,6 +25,7 @@
     "babel-plugin-un-cjs": "^2.3.0",
     "env-paths": "^2.2.0",
     "errorstacks": "^2.3.0",
+    "esbuild-jest": "^0.5.0",
     "jest": "^26.6.3",
     "jest-circus": "^26.6.3",
     "jscodeshift": "^0.11.0",