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no-value-tostring

Disallow calling .toString() on values that may not provide meaningful output.

⚠️ This rule requires type information to run.

Targeted pattern scope​

This rule targets .toString() and related stringification calls in typed TypeScript code.

What this rule reports​

This rule reports stringification that could produce unhelpful default object representations.

Why this rule exists​

Calling .toString() on broad object types can produce "[object Object]" instead of useful text. This rule reports potentially unsafe stringification.

❌ Incorrect​

const value: {} = {};
value.toString();

✅ Correct​

const value = 42;
value.toString();

Behavior and migration notes​

This rule forwards options to @typescript-eslint/no-base-to-string.

Additional examples​

declare const value: {};
String(value);
// ❌ reported by forwarded `no-base-to-string` behavior

declare const value: Date;
value.toString();
// ✅ valid

ESLint flat config example​

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

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

When not to use it​

Disable this rule if your codebase intentionally permits object default stringification and that behavior is covered by runtime tests.

Package documentation​

Rule catalog ID: R051

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.