Have got session creation working

assets/js/controllers/edit_upload.js

@@ -36,10 +36,15 @@ const processors = [
 ];
 
 export default class UploadEditController extends Controller {
-    static targets = ['processList'];
+    static targets = ['processList', 'preview'];
+    static values = {
+        uploadId: Number,
+        siteId: Number,
+    };
 
     connect() {
         this._rebuildProcessList();
+        this._createSession();
     }
 
     _rebuildProcessList() {
@@ -56,4 +61,22 @@ export default class UploadEditController extends Controller {
         el.innerHTML = cardOuter;
         // END TEMP
     }
+
+    async _createSession() {
+        try {
+            let resp = await fetch(`/sites/${this.siteIdValue}/imageedit/`, {
+                method: 'POST',
+                body: JSON.stringify({
+                    "base_upload": this.uploadIdValue,
+                })
+            });
+
+            this._state = await resp.json();
+            this.previewTarget.src = this._state.preview_url;
+
+            console.log("Session created");
+        } catch (e) {
+            console.error(e);
+        }
+    }
 }