fix: creating a Parse.File with base64 string fails

Closes #1510

Author: justinlettau

src/ParseFile.js

@@ -43,7 +43,7 @@ export type FileSource =
     };
 
 const base64Regex = new RegExp(
-  '([0-9a-zA-Z+/]{4})*(([0-9a-zA-Z+/]{2}==)|([0-9a-zA-Z+/]{3}=))',
+  '([0-9a-zA-Z+/]{4})*(([0-9a-zA-Z+/]{2}==)|([0-9a-zA-Z+/]{3}=)|([0-9a-zA-Z+/]{4}))',
   'i'
 );
 

src/__tests__/ParseFile-test.js

@@ -60,15 +60,21 @@ describe('ParseFile', () => {
     process.env.PARSE_BUILD = 'node';
   });
 
-  it('can create files with base64 encoding', () => {
-    const file = new ParseFile('parse.txt', { base64: 'ParseA==' });
-    expect(file._source.base64).toBe('ParseA==');
+  it('can create files with base64 encoding (no padding)', () => {
+    const file = new ParseFile('parse.txt', { base64: 'YWJj' });
+    expect(file._source.base64).toBe('YWJj');
     expect(file._source.type).toBe('');
   });
 
-  it('can create files with base64 encoding (no padding)', () => {
-    const file = new ParseFile('parse.txt', { base64: 'SGVsbG8gV29ybGQh' });
-    expect(file._source.base64).toBe('SGVsbG8gV29ybGQh');
+  it('can create files with base64 encoding (1 padding)', () => {
+    const file = new ParseFile('parse.txt', { base64: 'YWI=' });
+    expect(file._source.base64).toBe('YWI=');
+    expect(file._source.type).toBe('');
+  });
+
+  it('can create files with base64 encoding (2 padding)', () => {
+    const file = new ParseFile('parse.txt', { base64: 'ParseA==' });
+    expect(file._source.base64).toBe('ParseA==');
     expect(file._source.type).toBe('');
   });