JavaScript Promise.then回滚

Question

I have a model and a something like a store in my application. The model object is wait for the data from the store by using promise.

But for some cases I needs to delete the model, but because I use the promise my model is still in closure and GC isn't able to clean the object.

I'm looking for a way of how to remove the handler from the Promise object.

In the example below I creating two model objects and trying to remove one of them from the memory.

Also, by some cases the store.load method can be not executed at all during all application lifetime because this store.load method in the real application starts after some user activity. The store object has a single instance and lives forever during application lifecycle. And after couple of time the promise can keep a loot of objects and prevent models from deleting.

Could you suggest me a way of how to resolve this problem, or suggest another generic way.

Of course I can go bit away from the promise.

In common my logic is like: create a lot of UI elements wrapper (some of them will die somewhen, some of them will live forever), wait for some user activity, and when user caught application to load some data then model should use this data also.

  var createModel = function(dataStore, name) { var obj = { linkToDOM: { name: name, text: 'Here should be a link to the DOM object and etc.' }, init: function(data) { data.whenLoaded().then(this.run.bind(this)); }, run: function(data) { console.log('Do hard work with DOM and data', this.linkToDOM, data); }, remove: function() { delete this.linkToDOM; delete this.run; console.log('Can I go away? Pleaseee... Why not!?'); } }; obj.init(dataStore); return obj; }; var store = { _resolve: undefined, _loadPromise: undefined, init: function() { var self = this; this._loadPromise = new Promise(function(resolve) { self._resolve = resolve; }); }, whenLoaded: function() { return this._loadPromise; }, load: function() { var self = this; setTimeout(() => { self._resolve({msg: 'loaded', data: {a:1}}); }, 1000); } } store.init(); var model1 = createModel(store, 'model 1'); var model2 = createModel(store, 'model 2'); store.load(); // I don't need you any more! model1.remove(); 

Answer 1

Im not shure if its possible with real promises, thats why i simply write an own implementation:

function prom(){
console.log("prom registered");
this.funcs=[];
}
prom.prototype.then=function(func){
this.funcs.push(func);
console.log("callback added");
return this.funcs.length-1;
}
prom.prototype.resolve=function(){
this.funcs.forEach((func)=>{func();});
console.log("resolved");
}
prom.prototype.dismiss=function(id){
this.funcs.splice(id,1);
console.log("callback destroyed");
}

Use like this:

store=new Prom();
id=store.then(function(){});
store.dismiss(id);
store.resolve();//silence