ts-r
  • Error
  • Reported by the type checker

TS2390

Constructor implementation is missing.

A class declares constructor overloads but no constructor with a body. Add the implementation after the overload signatures.

What it means

Constructor overload signatures only describe how the class can be constructed. A class that isn't declared or abstract-only still needs one constructor with a body that handles every overload.

Example

index.ts
export class Point {
  constructor(x: number, y: number);
  constructor(xy: [number, number]);
}
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(3,3): error TS2390: Constructor implementation is missing.

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

  • Add a constructor with a body after the overloads, with parameters that accept every overload.
  • If the class only describes an existing value, use a declare class in a .d.ts file.