added ability to upgrade state in UrlHashBinding.updateFromUrlHash for backwards compatibilty

Author: chrisj

src/ui/default_viewer_setup.ts

@@ -161,7 +161,22 @@ export function setupDefaultViewer() {
       hashBinding.parseError;
     }),
   );
-  hashBinding.updateFromUrlHash();
+  hashBinding.updateFromUrlHash((state) => {
+    // convert graphene state timestamp to layer timestamp
+    const fixTimestamp = (layer: any) => {
+      if (layer.source?.state?.timestamp) {
+        layer.timestamp = layer.source.state.timestamp;
+        layer.source.state.timestamp = undefined;
+      }
+    };
+    if (state.layers) {
+      const layers = Array.isArray(state.layers)
+        ? state.layers
+        : Object.values(state.layers);
+      layers.map(fixTimestamp);
+    }
+    return state;
+  });
   viewer.registerDisposer(bindTitle(viewer.title));
 
   bindDefaultCopyHandler(viewer);

src/ui/url_hash_binding.ts

@@ -113,7 +113,7 @@ export class UrlHashBinding extends RefCounted {
    * Sets the current state to match the URL hash.  If it is desired to initialize the state based
    * on the URL hash, then this should be called immediately after construction.
    */
-  updateFromUrlHash() {
+  updateFromUrlHash(upgradeState: (a: any) => any = (x) => x) {
     try {
       let s = location.href.replace(/^[^#]+/, "");
       if (s === "" || s === "#" || s === "#!") {
@@ -160,7 +160,7 @@ export class UrlHashBinding extends RefCounted {
         this.root.reset();
         const state = urlSafeParse(s);
         verifyObject(state);
-        this.root.restoreState(state);
+        this.root.restoreState(upgradeState(state));
       } else {
         throw new Error(
           `URL hash is expected to be of the form "#!{...}" or "#!+{...}".`,