Validate that your components can safely be updated with fast refresh.

"Fast refresh", also known as "hot reloading", is a feature in many modern bundlers. If you update some React component(s) on disk, then the bundler will know to update only the impacted parts of your page -- without a full page reload.

eslint-plugin-react-refresh enforces that your components are structured in a way that integrations such as react-refresh expect.

⚠️ To avoid false positives, by default this plugin is only applied on tsx & jsx files. See Options to run on JS files. ⚠️

The plugin relies on naming conventions (i.e. use PascalCase for components, camelCase for util functions). This is why there are some limitations:

• export * are not supported and will be reported as an error
• Anonymous function are not supported (i.e export default function() {})
• Class components are not supported
• All-uppercase function export is considered an error when not using direct named export (ex const CMS = () => <></>; export { CMS })

npm i -D eslint-plugin-react-refresh

This plugin provides a single rule, react-refresh/only-export-components.

import reactRefresh from "eslint-plugin-react-refresh";

export default [
  {
    // in main config for TSX/JSX source files
    plugins: {
      "react-refresh": reactRefresh,
    },
    rules: {
      "react-refresh/only-export-components": "error",
    },
  },
];

{
  "plugins": ["react-refresh"],
  "rules": {
    "react-refresh/only-export-components": "error"
  }
}

These examples are from enabling react-refresh/only-exports-components.

export const foo = () => {};
export const Bar = () => <></>;

export default function () {}
export default compose()(MainComponent)

export * from "./foo";

const Tab = () => {};
export const tabs = [<Tab />, <Tab />];

const App = () => {};
createRoot(document.getElementById("root")).render(<App />);

export default function Foo() {
  return <></>;
}

const foo = () => {};
export const Bar = () => <></>;

import { App } from "./App";
createRoot(document.getElementById("root")).render(<App />);

These options are all present on react-refresh/only-exports-components.

interface Options {
  allowExportNames?: string[];
  allowConstantExport?: boolean;
  checkJS?: boolean;
}

const defaultOptions: Options = {
  allowExportNames: [],
  allowConstantExport: false,
  checkJS: false,
};

Default: []

If you use a framework that handles HMR of some specific exports, you can use this option to avoid warning for them.

Example for Remix:

{
  "react-refresh/only-export-components": [
    "error",
    { "allowExportNames": ["meta", "links", "headers", "loader", "action"] }
  ]
}

Default: false

Don't warn when a constant (string, number, boolean, templateLiteral) is exported aside one or more components.

This should be enabled if the fast refresh implementation correctly handles this case (HMR when the constant doesn't change, propagate update to importers when the constant changes.). Vite supports it, PR welcome if you notice other integrations works well.

{
  "react-refresh/only-export-components": [
    "error",
    { "allowConstantExport": true }
  ]
}

Enabling this option allows code such as the following:

export const CONSTANT = 3;
export const Foo = () => <></>;

Default: false

If your using JSX inside .js files (which I don't recommend because it forces you to configure every tool you use to switch the parser), you can still use the plugin by enabling this option. To reduce the number of false positive, only files importing react are checked.

{
  "react-refresh/only-export-components": ["error", { "checkJS": true }]
}