Typescript中的Openlayers JavaScript库

Question

we are working on a project using typescript. This is out first project with typescript. In this project we need to connect to a WFS server and this returns GML to us. Now to parse GML, we think of using the OpenLayers javascript library. I know there is a DefinitelyTyped version of Openlayers, but the GML parsing isn't ready yet.

So we tried to the javascript files. But i think we are missing something, because we are getting an error: Openlayers is undifined.

This is our code:

module PP.Data {
    declare var OpenLayers: any;
    export class WebRequest {

        public GetGML(url: string): XMLDocument {
            var retour: XMLDocument;
            var _this = this;
            $.ajax({
                url: url,
                type: 'GET',
                crossDomain: true,
                cache: false,
                async: false,
                dataType: 'xml'
            }).done(function (data) {
                var format = new OpenLayers.Format.GML();
                retour = format.read(data);
                });

            return retour;
        }
}
}

So the error starts when we try to create an instance of GML.

Any ideas?

Thanks!

Answer 1

OpenLayers is undefined.

Make sure OpenLayers is included (eg using a script tag) before you try to use it from typescript

Not related to error but noticed

You are effectively returning undefined here (as retour isn't assigned before its returned).

       .done(function (data) {
            var format = new OpenLayers.Format.GML();
                  retour = format.read(data);
            });

        return retour;

You should return the promise ie. the return value of the .done function OR have a callback. It needs to be async all the way down.