fetchingProperty for Knockout.js

/**
 * A Knockout Subscribable that is dependent on
 * an asynchronous function for fetching it's value,
 * such as a database call with a callback.
 *
 * @param {Function} fetcher The function that does the fetching of
 * the property value. The fetcher should accept
 * one argument, a setter, which is simply a function
 * that accepts the fetched value as it's single argument.
 * @param {Object} initialValue The initial value for the property (before the first fetch
 * has completed.)
 * @return {Subscribable} A Knockout Subscribable.
 */
 function fetchingProperty(fetcher, initialValue) {
 var cache = ko.observable(initialValue);

 var subComputed = computedLazy({
 deferEvaluation: true,
 read: function() {
 fetcher(cache);
 }
 });

 var firstRun = true;

 return computedLazy(function() {
 if (firstRun) {
 firstRun = false;
 subComputed();
 }
 return cache();
 })

 }

#javascript

#knockout

#mvvm