Enables obj instanceof MyStamp in ES6 environments

const InstanceOf = require('@stamp/instanceof');
// or
import InstanceOf from '@stamp/instanceof';

It uses the well known Symbol hasInstance to test instance.


Create a stamp:

let MyStamp = compose({
  properties: { ... },
  initializers: [function () { ... }]

The following doesn't work:

const obj = MyStamp();
obj instanceof MyStamp === false;

Compose the InstanceOf to your stamp:

MyStamp = MyStamp.compose(InstanceOf);

Now it works:

const myObject = MyStamp();
obj instanceof MyStamp === true;


  • We do not recommend to use instanceof in JavaScript in general.

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