@lankajs/plugin-devtools

⬡ plugin · Bus and transport inspector

The data is already collected and shown to nobody.

A core capability core does not implement itself. Registered with use(), then called by core. peerDependencies: lanka is mandatory.

Runs in: the browser.

How to use it: GUIDE.md — the user guide, with examples. How to change it: SKILL.md.

Extension point

Plugs into:

LankaLogger sinks · lankaEventBus.addMiddleware · lankaEventBus.addObserver · useRequestMiddleware · inFlight

Contents

• LankaDevtoolsCollector — bounded history of events, logs, requests and the scenario register
• renderLankaDevtoolsPanel — four tabs, a filter, clear and copy; absent outside development

A disabled inspector accumulates NOTHING

Its main property, pinned by its own test. Always-on history is a leak with a user interface: it looks like diagnostics and behaves as slow memory growth, visible only in a long session.

So the inspector has its OWN source, enabled together with it, and its own known buffer bound. Outside development it subscribes to nothing and returns an empty snapshot.

The inspector observes and does not decide

Its bus middleware always answers "pass". Able to stop delivery, a diagnostic tool would become a participant, and "disabled the inspector, it started working" would become a possible sentence.

Why stoppedBy needed a sixth extension point

A bus middleware sees only the chain AHEAD of itself, and a diagnostic tool's is the first one registered — so it could never learn that a later middleware stopped an event. The field existed and the guide described it; nothing filled it. lankaEventBus.addObserver reports the outcome of a dispatch after the whole chain has run, and cannot decide anything: a diagnostic tool that could stop an event would make "I disabled the inspector and it started working" a sentence somebody says.

The panel is absent from a production build

renderLankaDevtoolsPanel returns undefined before doing any work, so the consumer's bundler removes its body and everything it references. A panel in production is not a little extra code — it is an interface that can appear on a user's screen.

Repository map: ../../README.md