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no-mixed-enums

Disallow enum members that mix numeric and string representations.

Targeted pattern scope​

This rule targets TypeScript enum declarations.

What this rule reports​

This rule reports enums that mix member value kinds (for example, both string and numeric members).

Why this rule exists​

Mixed enum value kinds make comparisons and serialization rules harder to understand.

❌ Incorrect​

enum State {
 open = "open",
 closed = 2,
}

✅ Correct​

enum State {
 open = 1,
 closed = 2,
}

Behavior and migration notes​

This rule forwards options and behavior to @typescript-eslint/no-mixed-enums.

Additional examples​

enum NumericStatus {
 Open = 1,
 Closed = 2,
}
// ✅ valid

enum MixedStatus {
 Open = "open",
 Closed = 2,
}
// ❌ reported

ESLint flat config example​

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

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

When not to use it​

Disable this rule if mixed enums are required for compatibility with external wire formats.

Package documentation​

Rule catalog ID: R032

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.