instanceOf - API reference

API reference › @evolu/common › Type › instanceOf

function instanceOf<Constructor extends InstanceConstructor<object>>(
  constructor: ValidateInstanceConstructor<Constructor>,
): InstanceOfType<Constructor>;

Defined in: packages/common/src/Type.ts:4171

Instance Type for one constructor.

Membership uses the intrinsic prototype chain, so subclasses are accepted, equivalent constructors from other realms are rejected, and custom Symbol.hasInstance implementations are ignored.

Use object instead when only the structure matters.

Example

import { assertFalse, assertTrue, instanceOf } from "@evolu/common";

class User {
  readonly name: string;

  constructor(name: string) {
    this.name = name;
  }
}

const UserInstance = instanceOf(User);

assertTrue(UserInstance.is(new User("Ada")));
assertFalse(UserInstance.is({ name: "Ada" }));