Understanding Promise deprecation warnings in ArcGIS API for JavaScript?

BrienCrean — Mon, 05 Mar 2018 22:45:59 GMT

I am trying to update legacy map code to the latest ArcGIS version of 4.6 and noticed this warning in the console when querying a feature layer.

[esri.core.Promise] DEPRECATED: then() -- use .when(callback, errback) instead

So I tried to change then to when, but got when is not a function errors. I also tried running the sample code from the site and got the same errors.

view.whenLayerView(featureLayer).then(function(lyrView) {

lyrView.watch("updating", function(val) {

if (!val) { // wait for the layer view to finish updating

// query all the features available for drawing.

lyrView.queryFeatures().then(function(results) {

graphics = results;

var fragment = document.createDocumentFragment();

results.forEach(function(result, index) {

var attributes = result.attributes;

var name = attributes.ZIP + " (" +

attributes.PO_NAME + ")"

// Create a list zip codes in NY

var li = document.createElement("li");

li.classList.add("panel-result");

li.tabIndex = 0;

li.setAttribute("data-result-id", index);

li.textContent = name;

fragment.appendChild(li);

});

// Empty the current list

listNode.innerHTML = "";

listNode.appendChild(fragment);

});

}

});

I also tried setting the "esri-promise-compatibility" flag to 1 but that didn't help. Can't see anything in the docs or community forums about this. Anyone come across this before?

Re: Understanding Promise deprecation warnings in ArcGIS API for JavaScript?

RodrigoFelga — Tue, 06 Mar 2018 12:36:34 GMT

You need to replace then for when just when a class resolve to a promise. I don't see in you code any point to change, maybe the warning came from inside the api. Also happend to me to see warnings that came from inside the api and I can't resolve.

view.then(function(){});‍‍‍

view.when(function(){});‍‍‍

When a method resolve to a promise you don't need to change.

Read more here: Making Better Promises | ArcGIS Blog

Here is a list of classes that have a then method: Overview | API Reference | ArcGIS API for JavaScript 4.6

topic Re: Understanding Promise deprecation warnings in ArcGIS API for JavaScript? in ArcGIS JavaScript Maps SDK Questions

Understanding Promise deprecation warnings in ArcGIS API for JavaScript?

Re: Understanding Promise deprecation warnings in ArcGIS API for JavaScript?