no-declaration-only-without-declaration

Disallow emitDeclarationOnly: true without declaration: true, because declaration emit requires both options to be active.

Targeted pattern scope

The compilerOptions.emitDeclarationOnly and compilerOptions.declaration fields in any tsconfig*.json file.

What this rule reports

This rule reports when "emitDeclarationOnly": true is set but "declaration": true is absent or explicitly set to false.

Why this rule exists

emitDeclarationOnly is a modifier for the declaration option — it tells TypeScript to emit only .d.ts files without the corresponding JavaScript. Without declaration: true, TypeScript ignores emitDeclarationOnly entirely and emits no files at all. This means the option has no effect, making it dead configuration that silently misleads future maintainers.

The auto-fixer adds "declaration": true alongside the existing emitDeclarationOnly entry.

❌ Incorrect

{
    "compilerOptions": {
        "emitDeclarationOnly": true
    }
}

No .d.ts files will be emitted because declaration is implicitly false.

✅ Correct

{
    "compilerOptions": {
        "declaration": true,
        "emitDeclarationOnly": true
    }
}

If the project should emit both JavaScript and declarations, omit emitDeclarationOnly:

{
    "compilerOptions": {
        "declaration": true
    }
}

When not to use it

This rule should always be enabled. There is no valid use case for emitDeclarationOnly: true without declaration: true.

Package documentation

Rule catalog ID: R004

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

When not to use it​

Package documentation​

Further reading​