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no-const-enum

Disallow TypeScript const enum declarations.

Targeted pattern scope​

This rule inspects TSEnumDeclaration nodes and reports when the declaration is marked const.

With allowLocal: true, non-exported const enum declarations are allowed.

What this rule reports​

This rule reports const enum declarations. const enum relies on TypeScript-specific inlining behavior and can cause compatibility issues in mixed toolchains.

Why this rule exists​

const enum depends on compile-time inlining semantics that can break in mixed toolchains and isolated transpilation flows.

❌ Incorrect​

const enum Status {
 Ready,
 Running,
}

✅ Correct​

enum Status {
 Ready,
 Running,
}

Behavior and migration notes​

This rule reports only and does not provide an autofix.

Migration options:

  • convert const enum to regular enum, or
  • replace with as const object + union type.

Options​

type Options = {
 allowLocal?: boolean;
};

Default: { allowLocal: false }

allowLocal​

When true, non-exported const enum declarations are allowed.

Additional examples​

// config: { allowLocal: true }
const enum LocalKind {
 A,
}
// ✅ allowed when not exported

export const enum PublicKind {
 A,
}
// ❌ still reported

ESLint flat config example​

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

export default [
 {
  plugins: { "etc-misc": etcMisc },
  rules: {
   "etc-misc/no-const-enum": ["error", { allowLocal: true }],
  },
 },
];

When not to use it​

Disable this rule if your project explicitly depends on const enum inlining and your build toolchain guarantees consistent handling.

Package documentation​

Rule catalog ID: R021

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.