javascript - Reactive programming - value is greater than X for N seconds -

i have stream randstream emit random value every half second , boolstream converts value randstream boolean.

let randstream = kefir.frompoll(500, () => math.random()) let boolstream = kefir.map((rand) => rand > 0.5) 

i want emit true when boolstream emits true 5 seconds (in row). otherwise emit false.

i'm using kefir.js library.

do have ideas? thanks.

with given conditions when know exact rate @ randstream emit numbers, pretty easy achieve .slidingwindow:

let result = boolstream   .slidingwindow(10, 10)   .map(items => _.every(items))   .skipduplicates(); 

if want work rate of events, can try like:

let result = boolstream   .scan(({mostrecentfalse, latestvalue}, bool) => {     return bool ?        {mostrecentfalse, latestvalue: true} :        {mostrecentfalse: date.now(), lastvalue: false}   }, {mostrecentfalse: date.now()})   .changes()   .map(({mostrecentfalse, latestvalue}) =>      latestvalue && (date.now() - mostrecentfalse > 5000))   .skipduplicates();