knockout.js - Knockout js computed observable executed every time it is referenced -

knockout.js - Knockout js computed observable executed every time it is referenced -

i have view model in have observable array. have computed observable calculated 1 time observable array populated looping through items of array , computing computed observable.

this computed observable referenced in other computed observables. each time computed observable referenced looping done 1 time again. can whatever 1 suggest how can avoid this. computed observable executes looping once.

depending on how have declared computed observable (i'm assuming typical ko.computed(evaluator), every time read computed evaluator execute evaluate it.

considering have stated "this computed observable referenced in other computed observables", every 1 of references performing read.

in general, need "cache" result of processing.

the easiest way prevent duplicate processing not utilize computed straight in dependency chain. instead, within evaluator you'd modify other observable property of viewmodel , found dependencies on observable.

var vm = {data: ko.observablearray(), obs: ko.observable()} vm.modifiesmodelproperty = ko.computed(function(){ vm.obs("some evaluated look " + vm.data()) }) vm.anothercomputed = ko.computed(function(){ homecoming vm.obs(); })

if insistent on using computed , wanted encapsulate caching within it.

vm.computed = ko.computed({ owner: (function(){ var self = this; self.cachingobservable = ko.observable() vm.data.subscribe(function(nv){ self.cachingobservable("some evaluated look " + nv) }); })(), read: this.cachingobservable, })

you utilize combination of both approaches , set owner viewmodel , modify observable property way. in case, read homecoming observable.

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