feat: add option to run TypeScript diagnostics

By creating a `program` we are enabled to run diagnostics on typescipt files in order to emit semantic errors. For the time being I only used one of the many methods this one is `getPreEmitDiagnostics`

This enables syntactic & semantic TypeScript error reporting

README.md

@@ -329,9 +329,19 @@ By default Jest ignores everything in `node_modules`. This setting prevents Jest
 }
 ```
 ### TS compiler && error reporting
-- ts-jest only returns syntax errors from [tsc](https://github.com/Microsoft/TypeScript/issues/4864#issuecomment-141567247)
-- Non syntactic errors do not show up in [jest](https://github.com/facebook/jest/issues/2168)
-- If you only want to run jest if tsc does not output any errors, a workaround is `tsc --noEmit -p . && jest`
+If you want to enable Syntactic & Semantic TypeScript error reporting you can enable this through `enableTsDiagnostics` flag;
+
+```json
+{
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "enableTsDiagnostics": true
+      }
+    }
+  }
+}
+```
 
 ### Known Limitations for hoisting
 If the `jest.mock()` calls is placed after actual code, (e.g. after functions or classes) and `skipBabel` is not set,

src/jest-types.ts

@@ -74,4 +74,5 @@ export interface TsJestConfig {
   babelConfig?: BabelTransformOpts;
   tsConfigFile?: string;
   enableInternalCache?: boolean;
+  enableTsDiagnostics?: boolean;
 }

src/preprocessor.ts

@@ -7,6 +7,7 @@ import {
   cacheFile,
   getTSConfig,
   getTSJestConfig,
+  runTsDiagnostics,
   injectSourcemapHook,
 } from './utils';
 
@@ -41,14 +42,18 @@ export function process(
     return src;
   }
 
+  const tsJestConfig = getTSJestConfig(jestConfig.globals);
+  logOnce('tsJestConfig: ', tsJestConfig);
+
+  if (tsJestConfig.enableTsDiagnostics) {
+    runTsDiagnostics(filePath, compilerOptions);
+  }
+
   const tsTranspiled = tsc.transpileModule(src, {
     compilerOptions,
     fileName: filePath,
   });
 
-  const tsJestConfig = getTSJestConfig(jestConfig.globals);
-  logOnce('tsJestConfig: ', tsJestConfig);
-
   const postHook = getPostProcessHook(
     compilerOptions,
     jestConfig,