If you're still using tslint, I have bad news for you - it has been deprecated a long time ago. If tslint works for your old projects, then it's ok. However, for new projects use eslint. ESLint nowadays supports TypeScript with help of a plugin and parser. 

SharePoint Framework build pipeline is not as fast as the JavaScript tooling world and still uses tslint as a default linter. The good news is that we can fix it!

The source code for this post you can find on GitHub here.

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