ts-r
  • Error
  • Reported by the type checker

TS1030

'{0}' modifier already seen.

The same modifier is written twice on one declaration. Delete the repeated one.

What it means

A modifier such as readonly, static or abstract can appear only once on a declaration. It's reported on the second occurrence. Repeated accessibility modifiers are reported as TS1028 instead.

Example

index.ts
export class User {
  readonly readonly id = 1;
}
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(2,12): error TS1030: 'readonly' modifier already seen.

Recorded by node scripts/verify-examples.mjs with ts-r built from commit 6deaf01. The example uses the default tsconfig: strict, target: es2022, module: esnext, moduleResolution: bundler.

How to fix

  • Remove the duplicate modifier.