allow environment to transform the script before it's evaluated into …

…the vm
jestjs · Dec 3, 2018 · 38918f0 · 38918f0
1 parent 053b741
commit 38918f0
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Showing 3 changed files with 13 additions and 3 deletions.
diff --git a/packages/jest-runtime/src/index.js b/packages/jest-runtime/src/index.js
@@ -623,6 +623,7 @@ class Runtime {
         collectCoverage: this._coverageOptions.collectCoverage,
         collectCoverageFrom: this._coverageOptions.collectCoverageFrom,
         collectCoverageOnlyFrom: this._coverageOptions.collectCoverageOnlyFrom,
+        environment: this._environment,
         isInternalModule,
       },
       this._cacheFS[filename],

diff --git a/packages/jest-runtime/src/script_transformer.js b/packages/jest-runtime/src/script_transformer.js
@@ -14,6 +14,7 @@ import type {
   TransformResult,
 } from 'types/Transform';
 import type {ErrorWithCode} from 'types/Errors';
+import type {Environment} from 'types/Environment';
 
 import crypto from 'crypto';
 import path from 'path';
@@ -36,6 +37,7 @@ export type Options = {|
   collectCoverage: boolean,
   collectCoverageFrom: Array<Glob>,
   collectCoverageOnlyFrom: ?{[key: string]: boolean, __proto__: null},
+  environment?: Environment,
   isCoreModule?: boolean,
   isInternalModule?: boolean,
 |};
@@ -291,9 +293,7 @@ export default class ScriptTransformer {
   ): TransformResult {
     const isInternalModule = !!(options && options.isInternalModule);
     const isCoreModule = !!(options && options.isCoreModule);
-    const content = stripShebang(
-      fileSource || fs.readFileSync(filename, 'utf8'),
-    );
+    let content = stripShebang(fileSource || fs.readFileSync(filename, 'utf8'));
 
     let wrappedCode: string;
     let sourceMapPath: ?string = null;
@@ -305,6 +305,14 @@ export default class ScriptTransformer {
       (this._shouldTransform(filename) || instrument);
 
     try {
+      if (
+        options &&
+        options.environment &&
+        options.environment.transformScript
+      ) {
+        content = options.environment.transformScript(content);
+      }
+
       if (willTransform) {
         const transformedSource = this.transformSource(
           filename,

diff --git a/types/Environment.js b/types/Environment.js
@@ -18,6 +18,7 @@ export type EnvironmentOptions = {
 
 declare class $JestEnvironment {
   constructor(config: ProjectConfig, options?: EnvironmentOptions): void;
+  transformScript(script: string): string;
   runScript(script: Script): any;
   global: Global;
   fakeTimers: {