oxlint-plugin-react-memo-primitives

An oxlint JS plugin that enforces the use of React.memo for components with primitive props, flags React.memo used on components with no props or with a non-primitive prop, and requires a displayName on memoized components. This is the oxlint counterpart of eslint-plugin-react-memo-primitives, using oxlint's ESLint-compatible create(context) visitor API.

Rules

react-memo-primitives/require-memo-primitives

Flags a component (arrow function, function expression, or function declaration) that returns JSX and destructures a single object parameter of props, based on whether all of those props are primitive:

• If every prop is primitive and the component isn't wrapped in memo(...) / React.memo(...), memo is required.
• If any prop is non-primitive (object, function, ref, or other unresolvable type) and the component is wrapped in memo(...) / React.memo(...), memo is flagged as unnecessary.

When the parameter has a TS type annotation (oxlint parses .tsx natively), each prop's actual declared type is checked.

react-memo-primitives/no-unnecessary-memo

Flags a component wrapped in memo(...) / React.memo(...) that takes no props (no parameters, or an empty {} destructure).

react-memo-primitives/require-memo-displayname

Flags a component wrapped in memo(...) / React.memo(...) that has no Foo.displayName = ... assignment for its name, written as a direct top-level statement in the file.

Installation

npm install oxlint-plugin-react-memo-primitives --save-dev

Register the plugin in .oxlintrc.json:

{
  "jsPlugins": ["./node_modules/oxlint-plugin-react-memo-primitives/index.js"],
  "rules": {
    "react-memo-primitives/require-memo-primitives": "error",
    "react-memo-primitives/no-unnecessary-memo": "error",
    "react-memo-primitives/require-memo-displayname": "error"
  }
}

Or copy .oxlintrc.json from this package as a starting point.

Limitations

• oxlint's JS plugin API is currently alpha and not subject to semver — breaking changes are possible in future oxlint releases. Pin your oxlint version accordingly.
• oxlint's JS plugins have no access to a TypeScript type checker (type-aware linting is a native-Rust-only capability in oxlint, not exposed to JS plugins), and there's no upgrade path for this — unlike the ESLint package in this same monorepo, which can use a real checker when the consumer's config is type-aware. oxc parses .tsx type syntax natively though, so require-memo-primitives reads it directly: an inline object type or a same-file type/interface/enum reference is resolved and each member's declared type is checked. Objects, functions, arrays, tuples, and mapped types are always non-primitive; a reference resolved to a local enum is always primitive, resolved to a local object-shaped type it's non-primitive, resolved to a local primitive type alias it's unwrapped and checked recursively. A type that can't be resolved in the current file at all (imported from elsewhere, a generic parameter) falls back to a structural signal instead: a reference with type arguments (MutableRefObject<T>) is always non-primitive, while a bare reference with none (an imported enum or simple alias) is trusted as primitive. With no type annotation at all (plain JS/JSX), both rules fall back to the naming heuristic: a prop typed only by its destructured binding name (lowercase, not literally props) is treated as primitive regardless of its actual value.
• All three rules check that memo/React are actually imported from 'react' in the same file, so a same-named identifier imported from elsewhere isn't mistaken for real memoization. With no relevant import in the file at all, all three rules fall back to trusting the name.
• require-memo-displayname only recognizes a Foo.displayName = "..." assignment written as a direct top-level statement — one nested inside another function, conditional, or block isn't detected.

Testing

npm test

Runs the local oxlint binary against fixtures in test/fixtures/ (test/run.js, using oxlint's --format=json output) and asserts diagnostics land on exactly the expected lines.