@r1-dev/code-style

Opinionated oxlint and oxfmt configuration for TypeScript projects, in one package:

• an oxlint base config with a React add-on and an Effect add-on,
• the anti-slop rules, vendored,
• a padding-lines rule that enforces blank-line discipline, with an autofix,
• the oxfmt options.

The goal is code that reads the same in every repository that adopts it: one statement per thought, a blank line between thoughts, no function you cannot hold in your head.

Install

pnpm add -D @r1-dev/code-style oxlint oxfmt

oxlint (1.83 or later) and oxfmt (0.68 or later) are peer dependencies. The Node-based oxlint package and Node 22.18 or later are required, because the configs are TypeScript files.

Use

Two config files at the repository root. Each one imports the shared rules and adds only what is specific to that repository.

// oxlint.config.ts
import { base, react } from '@r1-dev/code-style/oxlint';
import { defineConfig } from 'oxlint';

export default defineConfig({
  extends: [base, react],
  ignorePatterns: ['src/generated/**']
});

// oxfmt.config.ts
import { format } from '@r1-dev/code-style/oxfmt';
import { defineConfig } from 'oxfmt';

export default defineConfig({
  ...format,
  sortImports: { ...format.sortImports, internalPattern: ['@acme/'] }
});

Leave out react in a project without React. Add effect in a project that uses Effect:

import { base, effect, react } from '@r1-dev/code-style/oxlint';

export default defineConfig({ extends: [base, react, effect] });

Add scripts:

{
  "scripts": {
    "lint": "oxlint",
    "lint:fix": "oxlint --fix",
    "format": "oxfmt",
    "format:check": "oxfmt --check"
  }
}

The first lint:fix and format on an existing codebase is a large commit. After that, the rules hold on every save and in CI.

What the rules say

Formatting (oxfmt)

| Option | Value | Why | | ------------------------------ | --------- | -------------------------------------------------------------- | | printWidth | 100 | Wide enough for a real name, narrow enough for two panes. | | semi | true | No ASI surprises. | | singleQuote | true | Less noise around the most common literal. | | trailingComma | "none" | A list ends where it ends. | | arrowParens | "always"| One shape for every arrow. | | experimentalOperatorPosition | "start" | A wrapped condition reads as a list of clauses. | | singleAttributePerLine | true | A JSX element with two attributes reads like an object. | | bracketSameLine | true | The closing > stays with the last attribute. | | sortImports | on | External, then internal, then relative, no groups by blank line. |

Linting (oxlint)

• The correctness, suspicious, and perf categories are errors.
• Type imports are explicit and inline: import { type Foo, bar }.
• Arrays are Array<T> and ReadonlyArray<T>, never T[].
• No console outside tests, seeds, scripts, and config files.
• complexity is capped at 10. A function past the cap is split into named steps. There is no autofix for this one by design.
• A long list of stylistic rules is turned off where the formatter or the type checker already decides, or where the rule fights idiomatic TypeScript (no-non-null-assertion, no-explicit-any, no-namespace, and others). See src/oxlint/index.ts.

anti-slop

base turns on every generic rule of anti-slop except require-readable-spacing, which r1/padding-lines covers. The rules reject low-evidence code: unknown parameters, returns, and type aliases; Record<string, unknown> contracts; typeof narrowing; chained or unexplained type assertions; filter().map() pairs; a reduce that copies its accumulator; object parameters; Reflect.get and Reflect.apply; module mocking; and shape words in names. oxc/no-accumulating-spread is on with them.

effect adds the five Effect rules: no hand-written _tag fields or comparisons, no hand-built tagged values, no imports of a service constructor outside its layer, and Match over a switch on a tag.

The plugins ship inside this package under @r1-dev/code-style/anti-slop and @r1-dev/code-style/anti-slop-effect. src/anti-slop/README.md records the vendored commit and the local edits.

r1/padding-lines

A blank line separates statements. Inside a function body a run of statements of the same tight kind stays together:

• imports,
• one-line variable declarations,
• plain calls,
• overload signatures with their implementation.

At the top level of a module every statement stands alone, except imports. A declaration, a statement that ends with a block, a function, class, interface, or type alias is always followed by a blank line. A return, throw, loop, if, switch, try, function, class, interface, type alias, or multi-line declaration always gets a blank line before it. The same rules apply inside a switch case. Comments travel with the statement under them: a blank line above a comment counts for that statement.

const rows = await load();
const first = rows[0];

if (first === undefined) return null;

if (first.isStale) return refresh(first);

for (const row of rows) {
  mark(row);
}

return first;

The rule is a configuration of the ESLint Stylistic padding-line-between-statements engine that anti-slop vendors, so it is autofixable: oxlint --fix inserts the missing lines and never removes any.

Compatibility

• oxlint 1.83 or later, Node-based package. JS plugins and TypeScript configs are marked experimental by oxlint; this package tracks them and pins a minimum.
• oxfmt 0.68 or later.
• Node 22.18 or later.

Versioning

Semantic versioning. A change that makes previously passing code fail lint or change under the formatter is a major version. New rules that are off by default, and fixes, are minor or patch. Every release is listed in CHANGELOG.md.

Contributing

See CONTRIBUTING.md. Rule proposals are welcome as issues that include a before-and-after code sample.

License

MIT. The vendored anti-slop and ESLint Stylistic code is MIT as well; their notices are in THIRD_PARTY_NOTICES.md, which ships with the package.