javascript - rxjs does a cold obs store all messages -

when reading an intro rxjs came read following , bit concerned

the second subscription restart sequence first value.

how start first value? store values in memory? real problem me using in worker/service stay running. if it's holding on them i'm headed massive blow up. thanks, r

standard subscriptions not buffer values. operators (and subjects) need buffer values implement behaviour (and buffer can unbounded) problem distinct hot vs. cold dichotomy.

the short explanation (cold) source observable (the upstream observable) knows how generate values when has subscriber. , generates same values subscribers. there no buffering, more regeneration of values. instance, rx.observable.range(1,10) knows values has generate, , generate them anytime there subscriber. not keep buffer 1,2,3...10 in memory, 1 , 10 , iterates in between generate values. same goes of cold observables, have value generating function associated them, , function reexecuted anew each subscriber.

if want switch behaviour observables in push values receive/generate them, existing subscribers @ moment of reception/generation, have convert cold observable hot one.

for more in-depth explanation, have @ illustrated subscription , data flows corresponding hot , cold observables.