Fix #38: allow filenames with dots

src/internal/source-checkers.ts

@@ -83,7 +83,7 @@ export const isIterable = (
  * Check, if given argument is simple string, and presumably is is just file name
  * I hope no one will wants to use filename longer than 50 symbols :)
  */
-const fileNameRE = /^[\p{L}\w\s\(\),-]+\.[A-Za-z0-9]+$/u // tslint:disable-line no-empty-character-class
+const fileNameRE = /^[\p{L}\w\s\(\).,-]+\.[A-Za-z0-9]+$/u // tslint:disable-line no-empty-character-class
 const MIN_FILE_NAME_LENGTH = 3
 const MAX_FILE_NAME_LENGTH = 50
 export const isFileName = (x: Source | undefined | null) =>

test/internal/source-checkers.spec.ts

@@ -50,6 +50,10 @@ test('Test `isFileName` function', function () {
   expect(isFileName('image.gif')).toBe(true) // <-
   expect(isFileName('中文.gif')).toBe(true) // <-
   expect(isFileName('عربي.jpg')).toBe(true) // <-
+  expect(isFileName('Screenshot 2021-12-24 at 09.16.20.png')).toBe(true) // <-
+  expect(isFileName('.test.png')).toBe(true) // <-
+  expect(isFileName('.png')).toBe(false)
+  expect(isFileName('🙀.png')).toBe(false)
   expect(isFileName(url)).toBe(false)
   expect(isFileName(array)).toBe(false)
   expect(isFileName(map)).toBe(false)