TS2392

#What it means

JavaScript classes have a single constructor. TypeScript lets you describe several ways to call it with overload signatures, but only one constructor may have a body.

#Example

export class Range {
  constructor(start: number) {}
  constructor(start: number, end: number) {}
}

index.ts(2,3): error TS2392: Multiple constructor implementations are not allowed.
index.ts(3,3): error TS2392: Multiple constructor implementations are not allowed.

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

• Keep one constructor with a body; give it optional parameters or a union so it covers every case.
• Write the other forms as overload signatures (no body) before it.
• Or add static factory methods such as Range.from(start, end).