@kontsedal/olas-eslint-plugin

ESLint rules for Olas apps. Each rule catches a mistake the types cannot see, such as a React hook in a controller factory, a definition that loses its identity or an async factory. Another keeps test helpers out of app code, and two rules guard optimistic writes. Two opt-in rules keep network calls out of components and make each request take its abort signal.

Install

pnpm add -D @kontsedal/olas-eslint-plugin eslint

eslint >= 9 is a peer dependency, and the plugin uses flat config. The tests run on ESLint 10. The rules read syntax only, so they need no type information. TypeScript files still need a parser, such as the one typescript-eslint sets up.

Setup

// eslint.config.js
import olas from '@kontsedal/olas-eslint-plugin'
import tseslint from 'typescript-eslint'

export default [...tseslint.configs.recommended, olas.configs.recommended]

olas.configs.strict adds the two opt-in rules and raises cancel-before-optimistic to an error.

The configs are typed with ESLint's own Linter.Config, so a typed eslint.config.ts accepts them as they are, in an array or through defineConfig. Each rule is named with the olas/ prefix, so one rule can be set on its own after a config:

export default [
  ...tseslint.configs.recommended,
  olas.configs.recommended,
  { rules: { 'olas/no-network-in-components': 'error' } },
]

Rules

| Rule | recommended | strict | Catches | |---|---|---|---| | no-react-hooks-in-controllers | error | error | A React hook inside a defineController factory. | | define-at-module-scope | error | error | defineQuery, defineInfiniteQuery, defineMutation or defineScope inside a function. | | no-async-controller-factory | error | error | An async factory, which makes the controller's api a promise. | | optimistic-returns-snapshot | error | error | A setData snapshot that onMutate does not return, or that other code discards. | | cancel-before-optimistic | warn | error | An optimistic setData in onMutate with no cancel on the same query before it. | | no-testing-outside-tests | error | error | @kontsedal/olas-core/testing imported from a file that is not a test. | | no-network-in-components | off | error | fetch or axios inside a React component. | | honor-abort-signal | off | error | A fetcher or mutate that does not read its signal, so a cancelled request runs to the end. |

Two rules take options. no-testing-outside-tests takes testFiles, the globs that count as tests. honor-abort-signal takes ignorePattern, for a context whose name marks work with nothing to abort, such as _ctx.

How it is checked

• tests/rules.test.ts runs every rule through @typescript-eslint/rule-tester, with valid and invalid cases.
• tests/examples.test.ts runs recommended and strict over the source and tests of every example app in this repo, and expects no findings. The first run found four real mistakes in the examples: three optimistic writes with no cancel first, and one leaked snapshot. It also found two false positives in define-at-module-scope. All six are fixed.