check-dts: Error when project has JavaScript files

If a project has JavaScript files (jest.config.js, for example), they are used in the check as well as TypeScript ones, which leads to errors. This pattern includes the JavaScript files: https://github.com/ai/check-dts/blob/c3ceea25aab9603c0a704126dfc7cd74401d1097/check.js#L67 all variable contains the files because of the pattern: https://github.com/ai/check-dts/blob/c3ceea25aab9603c0a704126dfc7cd74401d1097/check.js#L81 Then, the library tries to get errors from the files: https://github.com/ai/check-dts/blob/c3ceea25aab9603c0a704126dfc7cd74401d1097/check.js#L99 And inevitably fails at this point: https://github.com/ai/check-dts/blob/c3ceea25aab9603c0a704126dfc7cd74401d1097/check.js#L110 The error message is “TypeError: Cannot read property ‘text’ of undefined”.