Limited Availability

Observable

The when() method on a event target returns an Observable object, which provides a declarative API for subscribing to and operating on events. It's an alternative to addEventListener() callbacks.

Baseline Status: This feature is currently Limited (not yet Baseline). Latest engine implementation shipped on Apr 4, 2025.

Desktop Browser Engine Support

Google Chrome

135

Supported

Mozilla Firefox

—

Unsupported

Apple Safari

—

Unsupported

Microsoft Edge

135

Supported

Mobile Browser Engine Support

Chrome Android

135

Firefox Android

—

Safari iOS

—

Specifications and References

Specification ↗ Feature XML ↗

MDN Browser Compat Data Keys: