Use which sync interface

Author: leonardovillela

packages/jest-haste-map/src/crawlers/__tests__/node.test.js

@@ -124,7 +124,7 @@ jest.mock('fs', () => {
   };
 });
 
-jest.mock('which', () => jest.fn().mockResolvedValue());
+jest.mock('which');
 
 const pearMatcher = path => /pear/.test(path);
 const createMap = obj => new Map(Object.keys(obj).map(key => [key, obj[key]]));
@@ -296,7 +296,9 @@ describe('node crawler', () => {
   it('uses node fs APIs on Unix based OS without find binary', () => {
     process.platform = 'linux';
     const which = require('which');
-    which.mockReturnValueOnce(Promise.reject());
+    which.sync.mockImplementation(() => {
+      throw new Error();
+    });
 
     nodeCrawl = require('../node');
 
@@ -316,7 +318,7 @@ describe('node crawler', () => {
         }),
       );
       expect(removedFiles).toEqual(new Map());
-      expect(which).toBeCalledWith('find');
+      expect(which.sync).toBeCalledWith('find');
     });
   });
 

packages/jest-haste-map/src/crawlers/node.ts

@@ -22,12 +22,17 @@ type Result = Array<[/* id */ string, /* mtime */ number, /* size */ number]>;
 
 type Callback = (result: Result) => void;
 
-function hasNativeFindSupport(forceNodeFilesystemAPI: boolean): Promise<void> {
-  if (forceNodeFilesystemAPI) return Promise.reject();
+function hasNativeFindSupport(forceNodeFilesystemAPI: boolean): boolean {
+  if (forceNodeFilesystemAPI || process.platform === 'win32') {
+    return false;
+  }
 
-  return process.platform === 'win32'
-    ? Promise.reject()
-    : ((which('find') as unknown) as Promise<void>);
+  try {
+    which.sync('find');
+    return true;
+  } catch {
+    return false;
+  }
 }
 
 function find(
@@ -202,8 +207,10 @@ export = function nodeCrawl(
       });
     };
 
-    hasNativeFindSupport(forceNodeFilesystemAPI)
-      .then(() => findNative(roots, extensions, ignore, callback))
-      .catch(() => find(roots, extensions, ignore, callback));
+    if (hasNativeFindSupport(forceNodeFilesystemAPI)) {
+      findNative(roots, extensions, ignore, callback);
+    } else {
+      find(roots, extensions, ignore, callback);
+    }
   });
 };