feat: pass in wrapper arguments to transformer

CHANGELOG.md

@@ -30,6 +30,7 @@
 - `[jest-snapshot]` Improve colors when snapshots are updatable ([#9132](https://github.com/facebook/jest/pull/9132))
 - `[jest-snapshot]` Ignore indentation for most serialized objects ([#9203](https://github.com/facebook/jest/pull/9203))
 - `[jest-transform]` Create `createTranspilingRequire` function for easy transpiling modules ([#9194](https://github.com/facebook/jest/pull/9194))
+- `[jest-transform]` [**BREAKING**] Do not automatically wrap functions in a module wrapper ([#9253](https://github.com/facebook/jest/pull/9253))
 - `[@jest/test-result]` Create method to create empty `TestResult` ([#8867](https://github.com/facebook/jest/pull/8867))
 - `[jest-worker]` [**BREAKING**] Return a promise from `end()`, resolving with the information whether workers exited gracefully ([#8206](https://github.com/facebook/jest/pull/8206))
 - `[jest-reporters]` Transform file paths into hyperlinks ([#8980](https://github.com/facebook/jest/pull/8980))

packages/jest-runtime/src/index.ts

@@ -489,7 +489,7 @@ class Runtime {
       collectCoverage: this._coverageOptions.collectCoverage,
       collectCoverageFrom: this._coverageOptions.collectCoverageFrom,
       collectCoverageOnlyFrom: this._coverageOptions.collectCoverageOnlyFrom,
-      extraGlobals: this._config.extraGlobals,
+      moduleArguments: this.constructInjectedModuleArguments(),
     };
   }
 
@@ -1086,6 +1086,19 @@ class Runtime {
         formatStackTrace(stack, this._config, {noStackTrace: false}),
     );
   }
+
+  private constructInjectedModuleArguments() {
+    return [
+      'module',
+      'exports',
+      'require',
+      '__dirname',
+      '__filename',
+      'global',
+      'jest',
+      ...this._config.extraGlobals,
+    ];
+  }
 }
 
 Runtime.ScriptTransformer = ScriptTransformer;

packages/jest-transform/src/ScriptTransformer.ts

@@ -347,12 +347,12 @@ export default class ScriptTransformer {
   ): TransformResult {
     const isInternalModule = !!(options && options.isInternalModule);
     const isCoreModule = !!(options && options.isCoreModule);
-    const extraGlobals = (options && options.extraGlobals) || [];
+    const moduleArguments = (options && options.moduleArguments) || [];
     const content = stripShebang(
       fileSource || fs.readFileSync(filename, 'utf8'),
     );
 
-    let wrappedCode: string;
+    let scriptContent: string;
     let sourceMapPath: string | null = null;
     let mapCoverage = false;
 
@@ -369,19 +369,20 @@ export default class ScriptTransformer {
           instrument,
         );
 
-        wrappedCode = wrap(transformedSource.code, ...extraGlobals);
+        scriptContent = wrap(transformedSource.code, moduleArguments);
         sourceMapPath = transformedSource.sourceMapPath;
         mapCoverage = transformedSource.mapCoverage;
       } else {
-        wrappedCode = wrap(content, ...extraGlobals);
+        scriptContent = wrap(content, moduleArguments);
       }
 
       return {
         mapCoverage,
-        script: new Script(wrappedCode, {
+        script: new Script(scriptContent, {
           displayErrors: true,
           filename: isCoreModule ? 'jest-nodejs-core-' + filename : filename,
         }),
+        scriptContent,
         sourceMapPath,
       };
     } catch (e) {
@@ -412,7 +413,7 @@ export default class ScriptTransformer {
 
     if (!options.isCoreModule) {
       instrument = shouldInstrument(filename, options, this._config);
-      scriptCacheKey = getScriptCacheKey(filename, instrument);
+      scriptCacheKey = getScriptCacheKey(filename, instrument, options);
       const result = this._cache.transformedFiles.get(scriptCacheKey);
       if (result) {
         return result;
@@ -666,9 +667,19 @@ const readCacheFile = (cachePath: Config.Path): string | null => {
   return fileData;
 };
 
-const getScriptCacheKey = (filename: Config.Path, instrument: boolean) => {
+const getScriptCacheKey = (
+  filename: Config.Path,
+  instrument: boolean,
+  options: Options,
+) => {
   const mtime = fs.statSync(filename).mtime;
-  return filename + '_' + mtime.getTime() + (instrument ? '_instrumented' : '');
+  return (
+    filename +
+    '_' +
+    mtime.getTime() +
+    (instrument ? '_instrumented' : '') +
+    (options.moduleArguments ? options.moduleArguments.join('') : '')
+  );
 };
 
 const calcIgnorePatternRegExp = (config: Config.ProjectConfig) => {
@@ -699,26 +710,12 @@ const calcTransformRegExp = (config: Config.ProjectConfig) => {
   return transformRegexp;
 };
 
-const wrap = (content: string, ...extras: Array<string>) => {
-  const globals = new Set([
-    'module',
-    'exports',
-    'require',
-    '__dirname',
-    '__filename',
-    'global',
-    'jest',
-    ...extras,
-  ]);
-
-  return (
-    '({"' +
-    ScriptTransformer.EVAL_RESULT_VARIABLE +
-    `":function(${Array.from(globals).join(',')}){` +
-    content +
-    '\n}});'
-  );
-};
+const wrap = (content: string, moduleArguments: Array<string>) =>
+  '({"' +
+  ScriptTransformer.EVAL_RESULT_VARIABLE +
+  `":function(${moduleArguments.join(',')}){` +
+  content +
+  '\n}});';
 
 // TODO: Can this be added to the static property?
 ScriptTransformer.EVAL_RESULT_VARIABLE = 'Object.<anonymous>';

packages/jest-transform/src/__tests__/__snapshots__/script_transformer.test.js.snap

@@ -75,7 +75,7 @@ Object {
 `;
 
 exports[`ScriptTransformer transforms a file properly 1`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){/* istanbul ignore next */
+"({\\"Object.<anonymous>\\":function(){/* istanbul ignore next */
 function cov_25u22311x4() {
   var path = \\"/fruits/banana.js\\";
   var hash = \\"4be0f6184160be573fc43f7c2a5877c28b7ce249\\";
@@ -126,7 +126,7 @@ module.exports = \\"banana\\";
 `;
 
 exports[`ScriptTransformer transforms a file properly 2`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){/* istanbul ignore next */
+"({\\"Object.<anonymous>\\":function(){/* istanbul ignore next */
 function cov_23yvu8etmu() {
   var path = \\"/fruits/kiwi.js\\";
   var hash = \\"7705dd5fcfbc884dcea7062944cfb8cc5d141d1a\\";
@@ -221,12 +221,12 @@ module.exports = () => {
 `;
 
 exports[`ScriptTransformer transforms a file properly 3`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest,Math){module.exports = \\"banana\\";
+"({\\"Object.<anonymous>\\":function(){module.exports = \\"banana\\";
 }});"
 `;
 
 exports[`ScriptTransformer uses multiple preprocessors 1`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){
+"({\\"Object.<anonymous>\\":function(){
           const TRANSFORMED = {
             filename: '/fruits/banana.js',
             script: 'module.exports = \\"banana\\";',
@@ -237,7 +237,7 @@ exports[`ScriptTransformer uses multiple preprocessors 1`] = `
 `;
 
 exports[`ScriptTransformer uses multiple preprocessors 2`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){
+"({\\"Object.<anonymous>\\":function(){
           module.exports = {
             filename: /styles/App.css,
             rawFirstLine: root {,
@@ -247,12 +247,12 @@ exports[`ScriptTransformer uses multiple preprocessors 2`] = `
 `;
 
 exports[`ScriptTransformer uses multiple preprocessors 3`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){module.exports = \\"react\\";
+"({\\"Object.<anonymous>\\":function(){module.exports = \\"react\\";
 }});"
 `;
 
 exports[`ScriptTransformer uses the supplied preprocessor 1`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){
+"({\\"Object.<anonymous>\\":function(){
           const TRANSFORMED = {
             filename: '/fruits/banana.js',
             script: 'module.exports = \\"banana\\";',
@@ -263,7 +263,7 @@ exports[`ScriptTransformer uses the supplied preprocessor 1`] = `
 `;
 
 exports[`ScriptTransformer uses the supplied preprocessor 2`] = `
-"({\\"Object.<anonymous>\\":function(module,exports,require,__dirname,__filename,global,jest){module.exports = \\"react\\";
+"({\\"Object.<anonymous>\\":function(){module.exports = \\"react\\";
 }});"
 `;
 

packages/jest-transform/src/__tests__/script_transformer.test.js

@@ -685,4 +685,34 @@ describe('ScriptTransformer', () => {
       ['test_preprocessor', expect.any(Object)],
     ]);
   });
+
+  it('adds `moduleArguments` to transform wrapper', () => {
+    config = {...config, transform: [['^.+\\.js$', 'test_preprocessor']]};
+    const scriptTransformer = new ScriptTransformer(config);
+    const {scriptContent} = scriptTransformer.transform('/fruits/banana.js', {
+      moduleArguments: ['foo', 'bar', 'foobar'],
+    });
+
+    expect(scriptContent.split('\n')[0]).toEqual(
+      '({"Object.<anonymous>":function(foo,bar,foobar){',
+    );
+  });
+
+  it('moduleArguments should be part of cache key', () => {
+    config = {...config, transform: [['^.+\\.js$', 'test_preprocessor']]};
+    const scriptTransformer = new ScriptTransformer(config);
+    let result = scriptTransformer.transform('/fruits/banana.js', {});
+
+    expect(result.scriptContent.split('\n')[0]).toEqual(
+      '({"Object.<anonymous>":function(){',
+    );
+
+    result = scriptTransformer.transform('/fruits/banana.js', {
+      moduleArguments: ['foo', 'bar', 'foobar'],
+    });
+
+    expect(result.scriptContent.split('\n')[0]).toEqual(
+      '({"Object.<anonymous>":function(foo,bar,foobar){',
+    );
+  });
 });

packages/jest-transform/src/types.ts

@@ -12,15 +12,14 @@ import {Config} from '@jest/types';
 export type ShouldInstrumentOptions = Pick<
   Config.GlobalConfig,
   'collectCoverage' | 'collectCoverageFrom' | 'collectCoverageOnlyFrom'
-> & {
-  changedFiles?: Set<Config.Path>;
-};
+> & {changedFiles?: Set<Config.Path>};
 
 export type Options = ShouldInstrumentOptions &
-  Partial<Pick<Config.ProjectConfig, 'extraGlobals'>> & {
-    isCoreModule?: boolean;
-    isInternalModule?: boolean;
-  };
+  Partial<{
+    isCoreModule: boolean;
+    isInternalModule: boolean;
+    moduleArguments: Array<string>;
+  }>;
 
 // https://stackoverflow.com/a/48216010/1850276
 type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
@@ -38,6 +37,7 @@ export type TransformedSource = {
 
 export type TransformResult = {
   script: Script;
+  scriptContent: string;
   mapCoverage: boolean;
   sourceMapPath: string | null;
 };