TS2351

Expression is not constructable

This expression is not constructable.

The compiler’s own words. Not translated — this is the string you pasted into a search box.

The value after `new` has no construct signature, so it cannot create an instance.

Reproduction

const value = {}

new value()

The build asserts this emits exactly this code.

Why the compiler says this

`new` requires a class or constructor function whose type describes the instance it creates. An ordinary object is already a value; it is not a recipe for producing another one.

Fixes

class Value {
  readonly ok = true
}

const value = new Value()

Use a class when callers should construct distinct instances.

const makeValue = () => ({ ok: true })

const value = makeValue()

Use a factory call without `new` when a plain object is sufficient.

Takeaway

A construct signature describes what `new` can do. If the type has none, either the wrong value was imported or `new` does not belong there.

Where to go next

Type aliases Try it in the Lab

Errors