Chrome DevTools: Identify objects created with a certain constructor

Built into the DevTools Console is the Command Line API. You can use this JavaScript snippet:

queryObjects(Constructor)

To query for and retrieve objects which were created from the constructor you specify.

For example you can try:

queryObjects(WebSocket)
/*
If the above returns an empty array...
...try executing `new WebSocket('wss://url')` beforehand
*/

// Discover all Promise objects
queryObjects(Promise)

// Also works with user-defined constructors
class Person {}
new Person()
queryObjects(Person)