Roadmap: TSLint -> ESLint

[adidahiya]

As you may have read in this blog post, we plan to deprecate TSLint in 2019 and support the migration to ESLint as the standard linter for both TypeScript & JavaScript. This will not be an immediate deprecation; on the contrary, there is a lot of work to do to ensure a smooth transition to the new tooling without any regressions. There are features, test suites, and conveniences in TSLint which we hope to retain in the migration. There may be a period of time when there is overlap between the two tools and TSLint early adopters are recommended to run both linters to ensure full code check coverage (to a reasonable degree such that performance doesn't suffer drastically).

I will be closing some feature requests in this repo which now feel out of scope because we expect them to be handled in the ESLint / typescript-eslint roadmap. One example of a category of rules for which new feature requests are most likely to be closed / rejected is formatting rules. I have suggested splitting out these rules for quite some time because we use Prettier at Palantir and consider it a better tool for the job of formatting code.

TSLint will continue to release with important bug fixes and updates which keep it up-to-date with the latest compiler / language features.

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Update (June 2019): a more concrete roadmap timeline, coordinated with @JoshuaKGoldberg and tslint-contrib-microsoft:

• August 1st, 2019: Stop accepting new core rules. Still accept bug fixes, minor features, and rule enhancements. Custom rules are always an option and can be maintained outside this repo.
• November 1st, 2019: Stop accepting features or rule enhancements (with the exception of ones that make migrating to typescript-eslint easier). Still accept bug fixes.
• January 1st, 2020: Stop accepting anything except security fixes and fixes for crashes introduced by breaking TypeScript changes.
• December 1st, 2020: Stop accepting any PRs 🎉

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Update (August 2019): see tslint-to-eslint-config for a CLI command that migrates TSLint configuration files to ESLint configuration files.

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Update (March 2020): Added "and fixes for crashes introduced by breaking TypeScript changes" to the January 1st deadline, following discussion in #4914.

[felixfbecker]

I would be great to have a CLI command that migrates a tslint.json to an eslint.json, mapping equivalent rules and options. Ideally it would remove rules that can be migrated from tslint.json and keep rules that don't have an equivalent yet (or not support the used options), so that the rule can be run idempotently repeatedly over time until tslint.json becomes empty at some point and we can fully rely on ESLint.

[hinell]

Good news.
ESLint guys already started typescript-eslint project to support TS.
They are also looking for help. Here is the statement..