Fix typescript strict check errors

[tbouffard]

Fix TypeScript compilation errors. To ensure no new compilation errors are introduced, setup a GitHub workflow that check this on Pull Request and master branch.

closes #14

[tbouffard]

@hungtcs the worklow is currently not triggered. Can you check if the repository settings allow running actions from 3rd party please? This should work as described in https://help.github.com/en/actions/reference/events-that-trigger-workflows#pull-request-events-for-forked-repositories

[hungtcs]

Hi @tbouffard, the pull request not trigger workflow may be because the repository currently does not have a workflow, it only exists in the pull request, I created a test worklow, it will be trigger in the next pull request if nothing went wrong

[tbouffard]

Hi @tbouffard, the pull request not trigger workflow may be because the repository currently does not have a workflow, it only exists in the pull request, I created a test worklow, it will be trigger in the next pull request if nothing went wrong

@hungtcs you were totally right, I gave it a try by merging master into this PR branch, and the blank workflow and the newly introduce worklflow have been run.

• blank wf: https://github.com/hungtcs/mxgraph-type-definitions/pull/15/checks?check_run_id=821569593 : fail as expected
• new build wf: https://github.com/hungtcs/mxgraph-type-definitions/pull/15/checks?check_run_id=821569537 I am going to rebase the PR on the latest master

[tbouffard]

@hungtcs I have pushed all commits related to the contribution I wanted to do. Feel free to review it. Thanks again for helping me with the GitHub Workflow so quickly, it was great (as always) :smile_cat:

[hungtcs]

Thank you, @tbouffard