Use union type for source state

src/ol/renderer/Composite.js

@@ -5,7 +5,6 @@ import MapRenderer from './Map.js';
 import ObjectEventType from '../ObjectEventType.js';
 import RenderEvent from '../render/Event.js';
 import RenderEventType from '../render/EventType.js';
-import SourceState from '../source/State.js';
 import {CLASS_UNSELECTABLE} from '../css.js';
 import {checkedFonts} from '../render/canvas.js';
 import {inView} from '../layer/Layer.js';
@@ -115,8 +114,8 @@ class CompositeMapRenderer extends MapRenderer {
       const sourceState = layer.getSourceState();
       if (
         !inView(layerState, viewState) ||
-        (sourceState != SourceState.READY &&
-          sourceState != SourceState.UNDEFINED)
+        (layerState.sourceState != 'ready' &&
+          layerState.sourceState != 'undefined')
       ) {
         layer.unrender();
         continue;

src/ol/renderer/Layer.js

@@ -4,7 +4,6 @@
 import EventType from '../events/EventType.js';
 import ImageState from '../ImageState.js';
 import Observable from '../Observable.js';
-import SourceState from '../source/State.js';
 import {abstract} from '../util.js';
 
 /**
@@ -199,7 +198,7 @@ class LayerRenderer extends Observable {
     if (
       layer &&
       layer.getVisible() &&
-      layer.getSourceState() == SourceState.READY
+      'ready'
     ) {
       layer.changed();
     }

src/ol/renderer/webgl/TileLayer.js

@@ -2,7 +2,6 @@
  * @module ol/renderer/webgl/TileLayer
  */
 import LRUCache from '../../structs/LRUCache.js';
-import State from '../../source/State.js';
 import TileRange from '../../TileRange.js';
 import TileState from '../../TileState.js';
 import TileTexture from '../../webgl/TileTexture.js';
@@ -309,7 +308,7 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
     if (isEmpty(getRenderExtent(frameState, frameState.extent))) {
       return false;
     }
-    return source.getState() === State.READY;
+    return source.getState() === 'ready';
   }
 
   /**