fix(#909): Fixed issue where active elements within a shadowRoot would not be found by mask.

[andrewritchie]

Fixed an issue where active elements within a shadowRoot would not found by the mask service or directive, causing backspace to be handled improperly.

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/JsDaddy/ngx-mask/blob/develop/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features) - I do not believe sending a backspace keystroke to an input can be properly tested with Karma/Jasmine, no new unit tests has been added. Instead, an interactable component has been added to the bugs page.
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

Mask directive and service use document.activeElement to determine the active input element, which does not account for active elements within a Shadow DOM

Issue Number: #909

What is the new behavior?

Mask directive and service use new method to recursively determine the activeElement of shadowRoots. If no shadowRoot is found for the the document's active element, the directive and service continues to behave as before.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[zouhirjob]

the fix seem working and no comment for this change

[NepipenkoIgor]

@andrewritchie Hi. Awesome fix. Could you make reverse merge from develop ?

[goranvujanovic]

Hi. Any idea when this fix will be merged?

[NepipenkoIgor]

@goranvujanovic Hi. Looks like the latest changes broke the whole library . Needed to revert and repeat all from scratch. Please make reverse merge from actual develop