Fix GeoJSONSource#loaded sometimes returning true while there are sti…

…ll pending loads (maplibre#669) (maplibre#684)

* Fix GeoJSONSource#loaded sometimes returning true while there are still pending loads (maplibre#669)

* Add changelog entry

CHANGELOG.md

@@ -43,6 +43,7 @@
 - Fix type check for non dom environment. (#334)
 - Fix precision problem in patterns when overzoomed in OpenGL ES devices.
 - Fix padding-top of the popup to improve readability of popup text (#354).
+- Fix GeoJSONSource#loaded sometimes returning true while there are still pending loads (#669)
 
 ## 1.15.2
 

src/source/geojson_source.ts

@@ -75,7 +75,7 @@ class GeoJSONSource extends Evented implements Source {
     workerOptions: any;
     map: Map;
     actor: Actor;
-    _loaded: boolean;
+    _pendingLoads: number;
     _collectResourceTiming: boolean;
     _resourceTiming: Array<PerformanceResourceTiming>;
     _removed: boolean;
@@ -101,7 +101,7 @@ class GeoJSONSource extends Evented implements Source {
         this.isTileClipped = true;
         this.reparseOverscaled = true;
         this._removed = false;
-        this._loaded = false;
+        this._pendingLoads = 0;
 
         this.actor = dispatcher.getActor();
         this.setEventedParent(eventedParent);
@@ -265,7 +265,6 @@ class GeoJSONSource extends Evented implements Source {
      * using geojson-vt or supercluster as appropriate.
      */
     _updateWorkerData(callback: Callback<void>) {
-        this._loaded = false;
         const options = extend({}, this.workerOptions);
         const data = this._data;
         if (typeof data === 'string') {
@@ -275,16 +274,18 @@ class GeoJSONSource extends Evented implements Source {
             options.data = JSON.stringify(data);
         }
 
+        this._pendingLoads++;
+
         // target {this.type}.loadData rather than literally geojson.loadData,
         // so that other geojson-like source types can easily reuse this
         // implementation
         this.actor.send(`${this.type}.loadData`, options, (err, result) => {
+            this._pendingLoads--;
+
             if (this._removed || (result && result.abandoned)) {
                 return;
             }
 
-            this._loaded = true;
-
             if (result && result.resourceTiming && result.resourceTiming[this.id])
                 this._resourceTiming = result.resourceTiming[this.id].slice(0);
             // Any `loadData` calls that piled up while we were processing
@@ -300,7 +301,7 @@ class GeoJSONSource extends Evented implements Source {
     }
 
     loaded(): boolean {
-        return this._loaded;
+        return this._pendingLoads === 0;
     }
 
     loadTile(tile: Tile, callback: Callback<void>) {

test/unit/source/geojson_source.test.js

@@ -104,6 +104,19 @@ test('GeoJSONSource#setData', (t) => {
         source.setData('http://localhost/nonexistent');
     });
 
+    t.test('only marks source as loaded when there are no pending loads', (t) => {
+        const source = createSource();
+        source.once('data', () => {
+            t.notOk(source.loaded());
+            source.once('data', () => {
+                t.ok(source.loaded());
+                t.end();
+            });
+        });
+        source.setData({});
+        source.setData({});
+    });
+
     t.end();
 });