feat(jest-config): allow to use .js files in presets (jestjs#3564)

robin-drexler · Oct 21, 2017 · 4009c9a · 4009c9a
1 parent 0748e6f
commit 4009c9a
Show file tree

Hide file tree

Showing 2 changed files with 65 additions and 13 deletions.
diff --git a/packages/jest-config/src/__tests__/normalize.test.js b/packages/jest-config/src/__tests__/normalize.test.js
@@ -937,6 +937,44 @@ describe('preset', () => {
   });
 });
 
+describe('preset with .js file', () => {
+  beforeEach(() => {
+    const Resolver = require('jest-resolve');
+    Resolver.findNodeModule = jest.fn(name => {
+      if (name === 'react-native/jest-preset.json') {
+        return '/node_modules/react-native/jest-preset-dont-exist.json';
+      }
+      if (name === 'react-native/jest-preset.js') {
+        return '/node_modules/react-native/jest-preset.js';
+      }
+      return '/node_modules/' + name;
+    });
+    jest.mock(
+      '/node_modules/react-native/jest-preset.js',
+      () => ({
+        moduleNameMapper: {b: 'b'},
+        modulePathIgnorePatterns: ['js'],
+        setupFiles: ['b'],
+      }),
+      {virtual: true},
+    );
+  });
+  afterEach(() => {
+    jest.unmock('/node_modules/react-native/jest-preset.js');
+  });
+
+  it('should resolve jest-preset.js file', () => {
+    const normalized = normalize(
+      {
+        preset: 'react-native',
+        rootDir: '/root/path/foo',
+      },
+      {},
+    );
+    expect(normalized.options.modulePathIgnorePatterns).toEqual(['js']);
+  });
+});
+
 describe('preset without setupFiles', () => {
   let Resolver;
   beforeEach(() => {

diff --git a/packages/jest-config/src/normalize.js b/packages/jest-config/src/normalize.js
@@ -40,7 +40,20 @@ import setFromArgv from './set_from_argv';
 import VALID_CONFIG from './valid_config';
 const ERROR = `${BULLET}Validation Error`;
 const JSON_EXTENSION = '.json';
-const PRESET_NAME = 'jest-preset' + JSON_EXTENSION;
+const JS_EXTENSION = '.js';
+const PRESET_NAME = 'jest-preset';
+
+const requirePresetModule = (presetPath, rootDir): InitialOptions | null => {
+  try {
+    const presetModule = Resolver.findNodeModule(presetPath, {
+      basedir: rootDir,
+    });
+    // $FlowFixMe
+    return (require(presetModule): InitialOptions);
+  } catch (error) {
+    return null;
+  }
+};
 
 const createConfigError = message =>
   new ValidationError(ERROR, message, DOCUMENTATION_NOTE);
@@ -51,19 +64,20 @@ const setupPreset = (
 ): InitialOptions => {
   let preset;
   const presetPath = _replaceRootDirInPath(options.rootDir, optionsPreset);
-  const presetModule = Resolver.findNodeModule(
-    presetPath.endsWith(JSON_EXTENSION)
-      ? presetPath
-      : path.join(presetPath, PRESET_NAME),
-    {
-      basedir: options.rootDir,
-    },
-  );
 
-  try {
-    // $FlowFixMe
-    preset = (require(presetModule): InitialOptions);
-  } catch (error) {
+  if (presetPath.endsWith(JSON_EXTENSION)) {
+    preset = requirePresetModule(presetPath, options.rootDir);
+  } else {
+    [JSON_EXTENSION, JS_EXTENSION].some(extension => {
+      preset = requirePresetModule(
+        path.join(presetPath, PRESET_NAME + extension),
+        options.rootDir,
+      );
+      return preset !== null;
+    });
+  }
+
+  if (!preset) {
     throw createConfigError(`  Preset ${chalk.bold(presetPath)} not found.`);
   }