Add experimental next-swc jest transform

jest.config.js

@@ -1,3 +1,5 @@
+const path = require('path')
+
 module.exports = {
   testMatch: ['**/*.test.js', '**/*.test.ts', '**/*.test.tsx'],
   setupFilesAfterEnv: ['<rootDir>/jest-setup-after-env.ts'],
@@ -8,7 +10,7 @@ module.exports = {
   transform: {
     '.+\\.(t|j)sx?$': [
       // this matches our SWC options used in https://github.com/vercel/next.js/blob/canary/packages/next/taskfile-swc.js
-      '@swc/jest',
+      path.join(__dirname, './packages/next/jest.js'),
       {
         sourceMaps: 'inline',
         module: {

package.json

@@ -52,7 +52,6 @@
     "@svgr/webpack": "5.5.0",
     "@swc/cli": "0.1.49",
     "@swc/core": "1.2.97",
-    "@swc/jest": "0.2.3",
     "@testing-library/react": "11.2.5",
     "@types/cheerio": "0.22.16",
     "@types/fs-extra": "8.1.0",

packages/next/build/swc/jest.js

@@ -0,0 +1,133 @@
+/*
+Copyright (c) 2021 The swc Project Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+const fs = require('fs')
+const path = require('path')
+const vm = require('vm')
+const { transformSync } = require('./index')
+
+/**
+ * Loads closes package.json in the directory hierarchy
+ */
+function loadClosesPackageJson(attempts = 1) {
+  if (attempts > 5) {
+    throw new Error("Can't resolve main package.json file")
+  }
+  var mainPath = attempts === 1 ? './' : Array(attempts).join('../')
+  try {
+    return require(mainPath + 'package.json')
+  } catch (e) {
+    return loadClosesPackageJson(attempts + 1)
+  }
+}
+
+const packageConfig = loadClosesPackageJson()
+const isEsmProject = packageConfig.type === 'module'
+
+// Jest use the `vm` [Module API](https://nodejs.org/api/vm.html#vm_class_vm_module) for ESM.
+// see https://github.com/facebook/jest/issues/9430
+const isSupportEsm = 'Module' in vm
+
+let swcTransformOpts
+
+module.exports = {
+  process(src, filename, jestOptions) {
+    if (!/\.[jt]sx?$/.test(filename)) {
+      return src
+    }
+
+    if (!swcTransformOpts) {
+      swcTransformOpts = buildSwcTransformOpts(jestOptions)
+    }
+
+    if (isSupportEsm) {
+      set(
+        swcTransformOpts,
+        'module.type',
+        isEsm(filename, jestOptions) ? 'es6' : 'commonjs'
+      )
+    }
+
+    return transformSync(src, { ...swcTransformOpts, filename })
+  },
+}
+
+function buildSwcTransformOpts(jestOptions) {
+  let swcOptions = getSwcTransformConfig(jestOptions)
+
+  if (!swcOptions) {
+    const swcrc = path.join(process.cwd(), '.swcrc')
+    swcOptions = fs.existsSync(swcrc)
+      ? JSON.parse(fs.readFileSync(swcrc, 'utf-8'))
+      : {}
+  }
+
+  if (!isSupportEsm) {
+    set(swcOptions, 'module.type', 'commonjs')
+  }
+
+  set(swcOptions, 'jsc.transform.hidden.jest', true)
+
+  return swcOptions
+}
+
+function getSwcTransformConfig(jestConfig) {
+  return getJestConfig(jestConfig).transform.find(([, transformerPath]) =>
+    transformerPath.includes('next/jest')
+  )?.[2]
+}
+
+function getJestConfig(jestConfig) {
+  return 'config' in jestConfig
+    ? // jest 27
+      jestConfig.config
+    : // jest 26
+      jestConfig
+}
+
+function isEsm(filename, jestOptions) {
+  return (
+    (/\.jsx?$/.test(filename) && isEsmProject) ||
+    getJestConfig(jestOptions).extensionsToTreatAsEsm?.find((ext) =>
+      filename.endsWith(ext)
+    )
+  )
+}
+
+function set(obj, filepath, value) {
+  let o = obj
+  const parents = filepath.split('.')
+  const key = parents.pop()
+
+  for (const prop of parents) {
+    if (o[prop] == null) o[prop] = {}
+    o = o[prop]
+  }
+
+  o[key] = value
+}

packages/next/jest.js

@@ -0,0 +1 @@
+module.exports = require('./dist/build/swc/jest')

yarn.lock

@@ -4111,11 +4111,6 @@
     "@swc/core-win32-ia32-msvc" "1.2.97"
     "@swc/core-win32-x64-msvc" "1.2.97"
 
-"@swc/jest@0.2.3":
-  version "0.2.3"
-  resolved "https://registry.yarnpkg.com/@swc/jest/-/jest-0.2.3.tgz#5c32aaa6298267a955d35eb67094edabd5db598f"
-  integrity sha512-ARZIY5OkXdFRQLHc/1i+yKrl0H3B1sa7Bu9XE8yTvYZZ4G5Ewu6oyyJBM52TiROP6EpMcF7ZeQQsKMZvzuKkNw==
-
 "@szmarczak/http-timer@^1.1.2":
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/@szmarczak/http-timer/-/http-timer-1.1.2.tgz#b1665e2c461a2cd92f4c1bbf50d5454de0d4b421"