fix for decorator coverage

AUTHORS

@@ -25,6 +25,7 @@ Eric Anderson <e@ericlanderson.com>
 Felipe Matos <felipems@yahoo.com.br>
 Forbes Lindesay <forbes@lindesay.co.uk>
 Gino Zhang <whitetrefoil@gmail.com>
+Gregor Stamac <1668205+gstamac@users.noreply.github.com>
 Gustav Wengel <gustavwengel@gmail.com>
 Henry Zektser <japhar81@gmail.com>
 Ihor Chulinda <ichulinda@gmail.com>

README.md

@@ -33,6 +33,7 @@ ts-jest is a TypeScript preprocessor with source map support for Jest that lets
   - [Using `.babelrc`](#using-babelrc)
   - [Using a custom Babel config](#using-a-custom-babel-config)
   - [TS compiler & error reporting](#ts-compiler--error-reporting)
+  - [Ignore coverage on decorators](#ignore-coverage-on-decorators)
 - [Use cases](#use-cases)
   - [React Native](#react-native)
 - [Angular 2](#angular-2)
@@ -233,6 +234,25 @@ If you want to enable Syntactic & Semantic TypeScript error reporting you can en
 }
 ```
 
+### Ignore coverage on decorators
+
+**Note:** This is an experimental feature, comes with no guarantees and could be removed if it causes more problems than it solves
+
+If you want to ignore coverage on decorators you can enable this through `ignoreCoverageForDecorators` and `ignoreCoverageForAllDecorators` flags. If you enable the first option you have to add the `/* istanbul ignore decorator */` comment after the decorator. If you choose the second option all decorators will be ignored.
+
+```json
+{
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "ignoreCoverageForDecorators": true,
+        "ignoreCoverageForAllDecorators": true
+      }
+    }
+  }
+}
+```
+
 ## Use cases
 
 ### React Native

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-jest",
-  "version": "22.4.3",
+  "version": "22.4.4",
   "main": "index.js",
   "types": "./dist/index.d.ts",
   "description": "A preprocessor with sourcemap support to help use Typescript with Jest",

src/jest-types.ts

@@ -86,4 +86,6 @@ export interface TsJestConfig {
   enableInternalCache?: boolean;
   enableTsDiagnostics?: boolean;
   disableSourceMapSupport?: boolean;
+  ignoreCoverageForDecorators?: boolean;
+  ignoreCoverageForAllDecorators?: boolean;
 }

src/preprocessor.ts

@@ -55,14 +55,28 @@ export function process(
     fileName: filePath,
   });
 
+  let tsTranspiledText = tsTranspiled.outputText;
+  if (tsJestConfig.ignoreCoverageForAllDecorators === true) {
+    tsTranspiledText = tsTranspiledText.replace(
+      /__decorate/g,
+      '/* istanbul ignore next */__decorate',
+    );
+  }
+  if (tsJestConfig.ignoreCoverageForDecorators === true) {
+    tsTranspiledText = tsTranspiledText.replace(
+      /(__decorate\(\[\r?\n[^\n\r]*)\/\*\s*istanbul\s*ignore\s*decorator(.*)\*\//g,
+      '/* istanbul ignore next$2*/$1',
+    );
+  }
+
   const postHook = getPostProcessHook(
     compilerOptions,
     jestConfig,
     tsJestConfig,
   );
 
   const outputText = postHook(
-    tsTranspiled.outputText,
+    tsTranspiledText,
     filePath,
     jestConfig,
     transformOptions,
@@ -71,7 +85,7 @@ export function process(
   const modified =
     tsJestConfig.disableSourceMapSupport === true
       ? outputText
-      : injectSourcemapHook(filePath, tsTranspiled.outputText, outputText);
+      : injectSourcemapHook(filePath, tsTranspiledText, outputText);
 
   flushLogs();