Bugfix: clicking info panel before manifest loaded throws error. Closes #1880

__tests__/src/selectors/index.test.js

@@ -205,10 +205,10 @@ describe('getSelectedCanvas', () => {
     );
   });
 
-  it('should return an empty object when there is no manifestation to get a canvas from', () => {
+  it('should return undefined when there is no manifestation to get a canvas from', () => {
     const selectedCanvas = getSelectedCanvas(noManifestationState, 'a');
 
-    expect(selectedCanvas).toEqual({});
+    expect(selectedCanvas).toBeUndefined();
   });
 });
 
@@ -223,15 +223,14 @@ describe('getCanvasLabel', () => {
     expect(received).toBe('Whole Page');
   });
 
-  it('should return the given canvas index (+1) if the canvas is undefined', () => {
-    expect(getCanvasLabel(undefined)).toBe(1);
-    expect(getCanvasLabel(undefined, 2)).toBe(3);
+  it('should return undefined if the canvas is undefined', () => {
+    expect(getCanvasLabel(undefined)).toBeUndefined();
   });
 
-  it('should return the canvas index (+1) if no manifestation', () => {
-    const canvas = { getLabel: () => {} };
-    const received = getCanvasLabel(canvas);
-    expect(received).toBe(1);
+  it('should return the canvas index as (+1) as string if no label given', () => {
+    const canvas = { getLabel: () => [] };
+    const received = getCanvasLabel(canvas, 42);
+    expect(received).toBe('43');
   });
 });
 

src/containers/WindowSideBarInfoPanel.js

@@ -9,6 +9,7 @@ import {
   getManifestTitle,
   getSelectedCanvas,
   getWindowManifest,
+  getCanvasDescription,
 } from '../state/selectors';
 import WindowSideBarInfoPanel from '../components/WindowSideBarInfoPanel';
 
@@ -22,7 +23,7 @@ const mapStateToProps = (state, { windowId }) => ({
     getSelectedCanvas(state, windowId),
     state.windows[windowId].canvasIndex,
   ),
-  canvasDescription: getSelectedCanvas(state, windowId).getProperty('description'),
+  canvasDescription: getCanvasDescription(getSelectedCanvas(state, windowId)),
   canvasMetadata: getDestructuredMetadata(getSelectedCanvas(state, windowId)),
   manifestLabel: getManifestTitle(getWindowManifest(state, windowId)),
   manifestDescription: getManifestDescription(getWindowManifest(state, windowId)),

src/state/selectors/index.js

@@ -44,11 +44,11 @@ export function getSelectedCanvas(state, windowId) {
   const manifest = getWindowManifest(state, windowId);
   const { canvasIndex } = state.windows[windowId];
 
-  if (!manifest.manifestation) {
-    return {};
-  }
-
-  return manifest.manifestation.getSequences()[0].getCanvasByIndex(canvasIndex);
+  return manifest
+    && manifest.manifestation
+    && manifest.manifestation
+      .getSequences()[0]
+      .getCanvasByIndex(canvasIndex);
 }
 
 
@@ -99,10 +99,13 @@ export function getManifestDescription(manifest) {
 * @return {String|Integer}
 */
 export function getCanvasLabel(canvas, canvasIndex) {
-  return (canvas
-    && canvas.getLabel()
-    && canvas.getLabel().map(label => label.value)[0])
-    || (canvasIndex || 0) + 1;
+  if (!canvas) {
+    return undefined;
+  }
+  if (canvas.getLabel().length > 0) {
+    return canvas.getLabel().map(label => label.value)[0];
+  }
+  return String(canvasIndex + 1);
 }
 
 /**
@@ -122,3 +125,13 @@ export function getDestructuredMetadata(iiifResoruce) {
     }))
   );
 }
+
+/**
+* Return canvas description
+* @param {object} canvas
+* @param {String}
+*/
+export function getCanvasDescription(canvas) {
+  return canvas
+    && canvas.getProperty('description');
+}