✨ tsgolint ✨

tsgolint is an experimental proof-of-concept typescript-go powered JS/TS linter written in Go.

Important

tsgolint is a prototype in the early stages of development. It is not actively being worked on, nor is it expected to be production ready. See Goals and Non-Goals.

What's been prototyped

• Primitive linter engine
• Lint rules tester
• Source code fixer
• 40 type-aware typescript-eslint's rules
• Basic tsgolint CLI

Speedup over ESLint

tsgolint is 20-40 times faster than ESLint + typescript-eslint.

Most of the speedup is due to the following facts:

• Native speed parsing and type-checking (thanks to typescript-go)
• No more TS AST -> ESTree AST conversions. TS AST is directly used in rules.
• Parallel parsing, type checking and linting. tsgolint uses all available CPU cores.

See benchmarks for more info.

Implemented rules

Name	Status
await-thenable	✅
no-array-delete	✅
no-base-to-string	✅
no-confusing-void-expression	✅
no-duplicate-type-constituents	✅
no-floating-promises	✅
no-for-in-array	✅
no-implied-eval	✅
no-meaningless-void-operator	✅
no-misused-promises	✅
no-misused-spread	✅
no-mixed-enums	✅
no-redundant-type-constituents	✅
no-unnecessary-boolean-literal-compare	✅
no-unnecessary-template-expression	✅
no-unnecessary-type-arguments	✅
no-unnecessary-type-assertion	✅
no-unsafe-argument	✅
no-unsafe-assignment	✅
no-unsafe-call	✅
no-unsafe-enum-comparison	✅
no-unsafe-member-access	✅
no-unsafe-return	✅
no-unsafe-type-assertion	✅
no-unsafe-unary-minus	✅
non-nullable-type-assertion-style	✅
only-throw-error	✅
prefer-promise-reject-errors	✅
prefer-reduce-type-parameter	✅
prefer-return-this-type	✅
promise-function-async	✅
related-getter-setter-pairs	✅
require-array-sort-compare	✅
require-await	✅
restrict-plus-operands	✅
restrict-template-expressions	✅
return-await	✅
switch-exhaustiveness-check	✅
unbound-method	✅
use-unknown-in-catch-callback-variable	✅

What hasn't been prototyped

• Non-type-aware rules
• Editor extension
• Rich CLI features
• Config file
• Plugin system

What about JS plugins?

JS-based plugins are not currently supported.

• Experimental support is available on the experimental-eslint-compat branch using the goja JavaScript engine.
• While functional, performance was significantly worse than ESLint running in Node.js, so this approach is currently on hold.
• If a faster, lower-allocation JS interpreter in Go becomes available in the future, we may revisit this idea.

Goals and Non-Goals

tsgolint is an experiment. It is not under active development.

Goals: to explore architectures and performance characteristics. We want to investigate how much faster linting could be if we moved the linter to Go alongside typescript-go.

Non-Goals: we have no plans to take significant development budget away from typescript-eslint to work on tsgolint. Our plan is to continue to work on typescript-eslint to supported typed linting with ESLint. Experiments such as tsgolint should not be taken as indications of any project direction.

If you want faster typed linting with ESLint, see typescript-eslint/typescript-eslint#10940 Enhancement: Use TypeScript's Go port (tsgo / typescript-go) for type information.

Building tsgolint

git submodule update --init                       # init typescript-go submodule

cd typescript-go
git am --3way --no-gpg-sign ../patches/*.patch    # apply typescript-go patches
cd ..

go build -o tsgolint ./cmd/tsgolint