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default-case

Require a default branch in switch statements.

Targeted pattern scope​

This rule targets all JavaScript and TypeScript switch statements.

What this rule reports​

This rule reports switch statements that do not include a default case.

Why this rule exists​

Missing defaults can silently ignore unexpected values and create fragile control flow.

❌ Incorrect​

switch (status) {
 case "open":
  break;
}

✅ Correct​

switch (status) {
 case "open":
  break;
 default:
  break;
}

Behavior and migration notes​

This rule forwards options and behavior to ESLint core default-case.

Additional examples​

switch (kind) {
 case "a":
  runA();
  break;
}
// ❌ reported

switch (kind) {
 case "a":
  runA();
  break;
 default:
  throw new Error(`Unhandled kind: ${kind}`);
}
// ✅ valid

ESLint flat config example​

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

export default [
 {
  plugins: { "etc-misc": etcMisc },
  rules: {
   "etc-misc/default-case": "error",
  },
 },
];

When not to use it​

Disable this rule if you enforce exhaustive unions with explicit never checks and intentionally avoid default branches.

Package documentation​

Rule catalog ID: R011

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.