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no-underscore-export

Disallow underscore-prefixed named exports.

Targeted pattern scope​

This rule reports underscore-prefixed identifiers exported via named export declarations.

It targets:

  • exported function declarations,
  • exported declare function declarations,
  • exported variable declarator identifiers.

What this rule reports​

This rule reports exported declarations whose identifier starts with _.

Why this rule exists​

Underscore prefixes are often used for non-public/internal symbols. This rule prevents exposing those symbols as part of named exports.

❌ Incorrect​

export const _x = 1;
export function _f() {}

✅ Correct​

export const x = 1;
export function f() {}

Behavior and migration notes​

This rule reports only and does not provide an autofix.

Migration is usually renaming exported symbols or keeping underscore-prefixed values unexported.

Options​

This rule has no options.

Additional examples​

const _internal = 1;
export { _internal };
// ✅ currently not reported by this rule's selector coverage

export const _apiToken = "x";
// ❌ reported

ESLint flat config example​

import etcMisc from "eslint-plugin-etc-misc";

export default [
 {
  plugins: { "etc-misc": etcMisc },
  rules: {
   "etc-misc/no-underscore-export": "error",
  },
 },
];

When not to use it​

Disable this rule if underscore-prefixed exports are part of your public API conventions.

Package documentation​

Rule catalog ID: R044

Further reading​

Adoption resources​

  • Start at warning level in CI, then move to error after cleanup.
  • Use focused codemods/autofix batches per package or directory.