@crescware/eslint-plugin-crescware-const-no-upper-snake-case

ESLint plugin that forbids const declaration bindings named in SCREAMING_SNAKE_CASE. lowerCamelCase is preferred and PascalCase is allowed for components and classes. It ships as a standard ESLint plugin and is dogfooded on its own source through oxlint's JS plugin support.

Rule: crescware-const-no-upper-snake-case/const-no-upper-snake-case

Only SCREAMING_SNAKE_CASE binding names are rejected. A name is rejected when every character is an uppercase letter, a digit or an underscore and the first character is an uppercase letter — that is, it contains no lowercase letter at all:

• Rejected: NAME_MAX_LENGTH, ERROR_KEY, ANSWER, URL, and a single uppercase letter such as X.
• Allowed: lowerCamelCase (fooBar, getUrl) and PascalCase (Foo, BazComponent, QuxContext) for components and classes.
• A leading underscore (_keys, _) is allowed: the first character is not an uppercase letter.
• Any name containing at least one lowercase letter is allowed, because the rejection pattern admits no lowercase character.

What is checked

Every binding introduced by a const declaration, including:

• simple bindings (const fooBar = 1)
• object / array destructuring (const { a } = o, const [b] = arr)
• renamed destructuring — the local binding, not the source key (const { id: userId } = o checks userId)
• nested patterns, default values and rest elements
• for (const … of …) / for (const … in …) loop variables

What is not checked

let / var, function parameters, object property keys, type names, type parameters and import bindings are out of scope.

const fooBar = 1; // ok (lowerCamelCase)
const Foo = 1; // ok (PascalCase, e.g. a component or class)
const ANSWER = 1; // error: must not be SCREAMING_SNAKE_CASE
const { ERROR_KEY } = resp; // error on `ERROR_KEY`
let LOOSE_NAME = 1; // ok (not a const)

Usage (as a published ESLint plugin)

pnpm add -D @crescware/eslint-plugin-crescware-const-no-upper-snake-case

import constNoUpperSnakeCase from "@crescware/eslint-plugin-crescware-const-no-upper-snake-case";

export default [
  {
    plugins: {
      "crescware-const-no-upper-snake-case": constNoUpperSnakeCase,
    },
    rules: {
      "crescware-const-no-upper-snake-case/const-no-upper-snake-case": "error",
    },
  },
];

Stack

• Runtime: Node.js 24 (via mise)
• Package manager: pnpm (via corepack)
• Language: TypeScript (native preview)
• Test: Vitest
• Lint: oxlint
• Format: oxfmt
• Unused code: Knip

How it is built and verified

• src/index.ts is the plugin: a self-contained ESLint rule with no runtime dependencies. pnpm build compiles it to dist/ (with .d.ts) via tsconfig.build.json.
• .oxlintrc.json loads the plugin through jsPlugins: ["./src/index.ts"] and enables the rule on this repository's own source, so the plugin lints itself (no const in src/ is SCREAMING_SNAKE_CASE).
• fixtures/*.ts are lint fixtures: ng-*.ts must produce diagnostics and ok-*.ts must produce none. They are linted with the separate fixtures/oxlintrc.fixtures.json (all built-in categories off, only this rule on) and are excluded from the main lint via ignorePatterns.
• fixtures/integration.test.ts runs oxlint over the fixtures once and asserts the exact per-file diagnostic messages.

Setup

mise install
corepack enable
pnpm install

Scripts

| Command | Description | | -------------------- | ---------------------------------------------- | | pnpm build | Compile src/index.ts to dist/ with .d.ts | | pnpm check | Run all checks (types, lint, knip, test) | | pnpm check:types | Type check | | pnpm check:lint | Lint (incl. self-dogfooding) and format check | | pnpm check:knip | Unused files/exports check | | pnpm exec:fixtures | Print raw fixture diagnostics as JSON | | pnpm test | Run the fixture integration test | | pnpm format | Fix lint and format |