TypeScript 7 reference · Utility Types

TypeScript InstanceType<Type> Utility Type

Get the type of the object a class constructor creates, from the constructor's type.

TypeScript 7 Since 2.8

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Syntax

InstanceType<Type>

Parameters

Parameter	Description
`Type`	A constructor type (`typeof SomeClass`).

Return value

The instance type.

Examples

From typeof ClassTry it yourself

class Logger {
  constructor(public prefix: string) {}
  log(msg: string) {
    console.log(`${this.prefix} ${msg}`);
  }
}
type LoggerInstance = InstanceType<typeof Logger>;
const l: LoggerInstance = new Logger("[app]");
l.log("started");

Output

[app] started

A typed factoryTry it yourself

function make<C extends new (...args: any[]) => any>(Cls: C, ...args: ConstructorParameters<C>): InstanceType<C> {
  return new Cls(...args);
}
class Point {
  constructor(public x: number, public y: number) {}
}
const p = make(Point, 3, 4);
console.log(p.x + p.y, p instanceof Point);