can.onKeyValue
Used by can-reflect.onKeyValue to listen to when the underlying stream emits either a value
or error
with a new value.
stream[@@can.onKeyValue](key, handler)
can-reflect.onKeyValue will use this function
to listen to when emitted value
s or error
s change.
Notice how the following only logs 3 numbers even though 4 numbers are emitted:
import Kefir from "can-kefir";
const count = Kefir.sequentially( 1000, [ 1, 2, 2, 3 ] );
canReflect.onKeyValue( stream, "value", function( newVal ) {
console.log( "new value", newVal );
} ); // logs 1, 2, 3
Parameters
- key
{String}
:Either
value
for values emitted by the stream orerror
or error values emitted by the stream. - handler
{function(value)}
:A function handler that will be called when the emitted value changes with the emitted value.