restore generateEmptyCoverage

rely on babel for instrumentation

packages/jest-cli/src/generateEmptyCoverage.js

@@ -0,0 +1,30 @@
+/** 
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved. 
+ * 
+ * This source code is licensed under the BSD-style license found in the 
+ * LICENSE file in the root directory of this source tree. An additional grant 
+ * of patent rights can be found in the PATENTS file in the same directory. 
+ * 
+ * @flow 
+ */ 
+
+'use strict'; 
+
+import type {Config, Path} from 'types/Config'; 
+
+const IstanbulInstrument = require('istanbul-lib-instrument'); 
+
+const {transformSource, shouldInstrument} = require('jest-runtime'); 
+
+module.exports = function(source: string, filename: Path, config: Config) { 
+  if (shouldInstrument(filename, config)) { 
+    // Transform file without instrumentation first, to make sure produced 
+    // source code is ES6 (no flowtypes etc.) and can be instrumented 
+    source = transformSource(filename, config, source, false);
+    const instrumenter = IstanbulInstrument.createInstrumenter();
+    instrumenter.instrumentSync(source, filename); 
+    return instrumenter.fileCoverage;
+  } else { 
+    return null;
+  } 
+}; 

packages/jest-cli/src/reporters/CoverageReporter.js

@@ -16,10 +16,10 @@ import type {RunnerContext} from 'types/Reporters';
 const BaseReporter = require('./BaseReporter');
 
 const {clearLine} = require('jest-util');
-const {generateEmptyCoverageForSource} = require('jest-runtime');
 const {createReporter} = require('istanbul-api');
 const chalk = require('chalk');
 const fs = require('fs');
+const generateEmptyCoverage = require('../generateEmptyCoverage'); 
 const isCI = require('is-ci');
 const istanbulCoverage = require('istanbul-lib-coverage');
 const libSourceMaps = require('istanbul-lib-source-maps');
@@ -104,11 +104,7 @@ class CoverageReporter extends BaseReporter {
         if (!this._coverageMap.data[filename]) {
           try {
             const source = fs.readFileSync(filename).toString();
-            const coverage = generateEmptyCoverageForSource(
-              filename,
-              config,
-              source
-            );
+            const coverage = generateEmptyCoverage(source, filename, config);
             if (coverage) {
               this._coverageMap.addFileCoverage(coverage);
             }

packages/jest-runtime/package.json

@@ -13,7 +13,6 @@
     "babel-plugin-istanbul": "^3.0.0",
     "chalk": "^1.1.3",
     "graceful-fs": "^4.1.6",
-    "istanbul-lib-instrument": "^1.3.0",
     "jest-config": "^18.0.0",
     "jest-file-exists": "^17.0.0",
     "jest-haste-map": "^18.0.0",

packages/jest-runtime/src/index.js

@@ -166,14 +166,6 @@ class Runtime {
     return transform.transformSource(filename, config, content, instrument);
   }
 
-  static generateEmptyCoverageForSource(
-    filename: Path,
-    config: Config,
-    content: string,
-  ) {
-    return transform.generateEmptyCoverage(filename, config, content);
-  }
-
   static createHasteContext(
     config: Config,
     options: {

packages/jest-runtime/src/transform.js

@@ -17,7 +17,6 @@ const crypto = require('crypto');
 const fileExists = require('jest-file-exists');
 const fs = require('graceful-fs');
 const getCacheFilePath = require('jest-haste-map').getCacheFilePath;
-const IstanbulInstrument = require('istanbul-lib-instrument');
 const path = require('path');
 const shouldInstrument = require('./shouldInstrument');
 const stableStringify = require('json-stable-stringify');
@@ -298,33 +297,6 @@ const transformSource = (
   return result;
 };
 
-const generateEmptyCoverage = (
-  filename: Path,
-  config: Config,
-  content: string
-): Object => {
-  const transform = getTransformer(filename, config);
-  let source = content;
-
-  if (transform && shouldTransform(filename, config)) {
-    if (
-      transform.canInstrument &&
-      typeof transform.getEmptyCoverage === 'function'
-    ) {
-      return transform.getEmptyCoverage(content, filename, config, {
-        instrument: true,
-        watch: config.watch,
-      });
-    } else {
-      source = transformSource(filename, config, content, false);
-    }
-  }
-
-  const instrumenter = IstanbulInstrument.createInstrumenter();
-  instrumenter.instrumentSync(source, filename);
-  return instrumenter.lastFileCoverage();
-};
-
 const transformAndBuildScript = (
   filename: Path,
   config: Config,
@@ -384,4 +356,3 @@ module.exports = (
 
 module.exports.EVAL_RESULT_VARIABLE = EVAL_RESULT_VARIABLE;
 module.exports.transformSource = transformSource;
-module.exports.generateEmptyCoverage = generateEmptyCoverage;