Merge pull request #234 from forcedotcom/mdonnalley/add-fs-fileExists

feat: add fs.fileExists

src/util/fs.ts

@@ -158,5 +158,19 @@ export const fs = {
       encoding: 'utf8',
       mode: fs.DEFAULT_USER_FILE_MODE
     });
+  },
+
+  /**
+   * Checks if a file path exists
+   *
+   * @param filePath the file path to check the existence of
+   */
+  fileExists: async (filePath: string): Promise<boolean> => {
+    try {
+      await fs.access(filePath);
+      return true;
+    } catch (err) {
+      return false;
+    }
   }
 };

test/unit/util/fsTest.ts

@@ -213,4 +213,17 @@ describe('util/fs', () => {
       });
     });
   });
+
+  describe('fileExists', () => {
+    it('should return true if the file exists', async () => {
+      $$.SANDBOX.stub(fs, 'access').returns(Promise.resolve(true));
+      const exists = await fs.fileExists('foo/bar.json');
+      expect(exists).to.be.true;
+    });
+
+    it('should return false if the file does not exist', async () => {
+      const exists = await fs.fileExists('foo/bar.json');
+      expect(exists).to.be.false;
+    });
+  });
 });