diff --git a/packages/babel-jest/src/index.ts b/packages/babel-jest/src/index.ts
index 5a23c4fdb1d9..705502120562 100644
--- a/packages/babel-jest/src/index.ts
+++ b/packages/babel-jest/src/index.ts
@@ -10,7 +10,7 @@ import * as path from 'path';
 import * as fs from 'graceful-fs';
 import type {
   TransformOptions as JestTransformOptions,
-  Transformer,
+  SyncTransformer,
 } from '@jest/transform';
 import type {Config} from '@jest/types';
 import {
@@ -29,7 +29,7 @@ const jestPresetPath = require.resolve('babel-preset-jest');
 const babelIstanbulPlugin = require.resolve('babel-plugin-istanbul');
 
 // Narrow down the types
-interface BabelJestTransformer extends Transformer {
+interface BabelJestTransformer extends SyncTransformer {
   canInstrument: true;
 }
 interface BabelJestTransformOptions extends TransformOptions {
diff --git a/packages/jest-repl/src/cli/repl.ts b/packages/jest-repl/src/cli/repl.ts
index 0b49eb045d39..579e91ae527e 100644
--- a/packages/jest-repl/src/cli/repl.ts
+++ b/packages/jest-repl/src/cli/repl.ts
@@ -24,7 +24,7 @@ const evalCommand: repl.REPLEval = (
 ) => {
   let result;
   try {
-    if (transformer) {
+    if (transformer && transformer.process) {
       const transformResult = transformer.process(
         cmd,
         jestGlobalConfig.replname || 'jest.js',
diff --git a/packages/jest-transform/src/ScriptTransformer.ts b/packages/jest-transform/src/ScriptTransformer.ts
index acb4d0108024..8334b787f35f 100644
--- a/packages/jest-transform/src/ScriptTransformer.ts
+++ b/packages/jest-transform/src/ScriptTransformer.ts
@@ -34,6 +34,7 @@ import type {
 } from './types';
 import shouldInstrument from './shouldInstrument';
 import handlePotentialSyntaxError from './enhanceUnexpectedTokenMessage';
+import VERSION from './version';
 
 type ProjectCache = {
   configString: string;
@@ -42,8 +43,6 @@ type ProjectCache = {
   transformedFiles: Map<string, TransformResult>;
 };
 
-// Use `require` to avoid TS rootDir
-const {version: VERSION} = require('../package.json');
 
 // This data structure is used to avoid recalculating some data every time that
 // we need to transform a file. Since ScriptTransformer is instantiated for each
diff --git a/packages/jest-transform/src/index.ts b/packages/jest-transform/src/index.ts
index a104f5197968..de3fb66a3bfb 100644
--- a/packages/jest-transform/src/index.ts
+++ b/packages/jest-transform/src/index.ts
@@ -13,6 +13,8 @@ export {default as shouldInstrument} from './shouldInstrument';
 export type {
   CacheKeyOptions,
   Transformer,
+  SyncTransformer,
+  AsyncTransformer,
   ShouldInstrumentOptions,
   Options as TransformationOptions,
   TransformOptions,
diff --git a/packages/jest-transform/src/version.ts b/packages/jest-transform/src/version.ts
new file mode 100644
index 000000000000..4da7e89ed84d
--- /dev/null
+++ b/packages/jest-transform/src/version.ts
@@ -0,0 +1,4 @@
+// Use `require` to avoid TS rootDir
+const {version: VERSION} = require('../package.json');
+
+export default VERSION;
\ No newline at end of file
diff --git a/packages/jest-transform/tsconfig.json b/packages/jest-transform/tsconfig.json
index 86498ca1e5cf..c3c126149d3f 100644
--- a/packages/jest-transform/tsconfig.json
+++ b/packages/jest-transform/tsconfig.json
@@ -1,7 +1,8 @@
 {
   "extends": "../../tsconfig.json",
   "compilerOptions": {
-    "outDir": "build"
+    "outDir": "build",
+    "rootDir": "src",
   },
   "references": [
     {"path": "../jest-haste-map"},
@@ -9,5 +10,4 @@
     {"path": "../jest-types"},
     {"path": "../jest-util"}
   ],
-  "include": ["src/**/*", "package.json"], 
 }