eslint-config-deepcrawl

eslint-config

ESLint rules used by Lumar (formerly DeepCrawl).

Installation

Add eslint-config-deepcrawl and its peer dependencies to your package.json:

yarn add --dev \
  eslint-config-deepcrawl \
  eslint@^10.0.0

Usage

Update your eslint.config.mjs file:

import eslintConfigDeepcrawl from "eslint-config-deepcrawl";

export default [...eslintConfigDeepcrawl];

Recommendations

TypeScript

Have these options enabled in your tsconfig.json file:

{
  "compilerOptions": {
    "noImplicitAny": true,
    "strictPropertyInitialization": true
  }
}

or enable @typescript-eslint/typedef rule.

Prettier

Apart from ESLint, it is recommended to use the following Prettier configuration:

{
  "arrowParens": "avoid",
  "bracketSpacing": true,
  "endOfLine": "lf",
  "plugins": ["prettier-plugin-packagejson"],
  "printWidth": 120,
  "quoteProps": "as-needed",
  "semi": true,
  "singleQuote": false,
  "tabWidth": 2,
  "trailingComma": "all",
  "useTabs": false
}

with lint-staged pre-commit hook done via husky.

Migrating from v16

v17 replaces eslint-plugin-jest with @vitest/eslint-plugin. To upgrade:

1. Rename every jest/* rule reference in your eslint.config.* to vitest/*. For example, "jest/expect-expect" becomes "vitest/expect-expect". ESLint silently ignores unknown rule names set to "off", so if you miss a rename, your override stops working without an error.

2. If you still use Jest, the same rules lint Jest tests, because the test APIs are largely compatible. However, these rules are gone: no-deprecated-functions, no-export and no-jasmine-globals have no Vitest equivalent, and vitest/no-done-callback is deprecated because Vitest does not support done callbacks. The Jest-only globals (jest, fit, xit, xtest, xdescribe) are no longer declared either.

3. @typescript-eslint/unbound-method is replaced by vitest/unbound-method in TypeScript files. The Vitest rule reports the same problems but allows passing a method to expect() (for example expect(client.getAccount).toHaveBeenCalled()) and to vi.mocked(). Rename any eslint-disable comments and config overrides for @typescript-eslint/unbound-method to vitest/unbound-method. Remove the disable comments that only worked around mock expectations. Old disable comments are reported as unused.

4. Vitest globals are required. vitest/no-importing-vitest-globals reports imports of describe, it, expect, vi and the other globals from vitest. Type imports such as Mock are still allowed. Enable globals in your Vitest config and add the global types to your tsconfig.json:

   // vitest.config.ts
   export default defineConfig({ test: { globals: true } });

   { "compilerOptions": { "types": ["vitest/globals"] } }

   eslint --fix removes the imports.

5. Tests must use it, not test, both at the top level and inside describe (vitest/consistent-test-it). eslint --fix renames them.

6. These rules are new. Most of them can be fixed with eslint --fix:

   • From the Vitest recommended preset: vitest/no-import-node-test, vitest/no-unneeded-async-expect-function, vitest/prefer-called-exactly-once-with and vitest/require-local-test-context-for-concurrent-snapshots.
   • Added by this config: vitest/no-test-return-statement, vitest/prefer-comparison-matcher, vitest/prefer-equality-matcher, vitest/prefer-hooks-in-order, vitest/prefer-hooks-on-top, vitest/prefer-mock-promise-shorthand, vitest/prefer-to-contain, vitest/prefer-to-have-length, vitest/prefer-todo, vitest/prefer-vi-mocked and vitest/require-awaited-expect-poll.

Migrating from v15

v16.0.0 fixed the @stylistic/max-len ignore pattern, which had been exempting every line, so long lines started to report errors. v16.0.1 then removed @stylistic/max-len altogether and left line length to Prettier. If you upgrade straight to v16.0.1 or later, you don't need to change anything. If you added overrides to work around v16.0.0, you can remove them.

Migrating from v14

v15 upgrades to ESLint 10 and replaces eslint-plugin-import with its maintained fork eslint-plugin-import-x. To upgrade:

1. Bump eslint to ^10.0.0 (drop ESLint 9).
2. Rename every import/* rule reference in your eslint.config.* to import-x/* — e.g. "import/no-default-export" → "import-x/no-default-export". ESLint silently ignores unknown rule names set to "off", so a missed rename turns into a silent loss of your override.
3. Remove @types/eslint__js from your devDependencies if you have it — @eslint/js@10 now ships its own type definitions.

No other consumer changes are required; the rest of the ruleset is unchanged.