AVAListen to events
AVA extends the AntV event emitter. Listen with string event names; event constants are not re-exported by the public package entry points.
ava.on('translatestart', (event) => {
console.log('Translating:', event.data);
});
ava.on('queryend', (event) => {
console.log('Query completed:', event.data);
});Each emitted event has type and data. End events can include a serialized error; receiving an end event alone does not imply success.
Listener parameters
These inherited methods are synchronous. on(), once(), and off() return the emitter.
| Method | Parameter | Type | Required / default |
|---|---|---|---|
on(evt, callback, once?) | evt | string | Required event name. |
on(evt, callback, once?) | callback | Function | Required listener; receives the emitted event. |
on(evt, callback, once?) | once | boolean | Optional; false; remove after one invocation when true. |
once(evt, callback) | evt | string | Required event name. |
once(evt, callback) | callback | Function | Required one-time listener. |
off(evt?, callback?) | evt | string | Optional; omit to remove all listeners. |
off(evt?, callback?) | callback | Function | Optional; omit to remove every listener for the event. |
emit(evt, ...args) | evt | string | Required event name to emit manually. |
emit(evt, ...args) | args | any[] | Optional rest arguments passed to listeners. |
emit() returns no value. getEvents() takes no parameters and returns the emitter's listener registry. Use off() with the same function reference that was passed to on() to remove a particular listener.
Event pairs
| Stage | Start / end |
|---|---|
| Engine creation | createstart / createend |
| Engine cleanup | disposestart / disposeend |
| Source loading | loadstart / loadend |
| Profiling | profilestart / profileend |
| Analysis | analyzestart / analyzeend |
| Translation | translatestart / translateend |
| Query execution | querystart / queryend |
| Summarization | summarizestart / summarizeend |
| Subset selection | selectcontextstart / selectcontextend |
| Loop reasoning | reasonstart / reasonend |
| Visualization | visualizestart / visualizeend |
| Suggestions | suggeststart / suggestend |
Lifecycle
Engine creation happens when source() is called, not in the constructor. Replacing a source disposes the previous engine. dispose() clears the engine, schema, and latest profile.
Translation events may include query, attempt, or generated dsl; query events include the DSL or execution result. Reasoning events expose the loop step and action. These are useful for progress UI and diagnostics.