ts-r
  • Error
  • Reported by the type checker

TS2351

This expression is not constructable.

`new` is used on a value that has no construct signature. Make sure it's a class or constructor.

What it means

new X() needs X to have a construct signature, such as a class. Using new on an object, an instance or another value without one is reported here, with a second line naming the type. (With noImplicitAny, new on a plain function expression is reported as TS7009 instead.)

Example

index.ts
const settings = { theme: "dark" };

export const s = new settings();
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(3,22): error TS2351: This expression is not constructable.
  Type '{ theme: string; }' has no construct signatures.

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

  • Call it without new if it's a plain function.
  • Use a class if you need instances.