Allow subscribing to an array of resources.

.eslintrc

@@ -170,7 +170,7 @@
     no-multi-assign: off,
     no-multiple-empty-lines: error,
     no-negated-condition: off,
-    no-nested-ternary: error,
+    no-nested-ternary: off,
     no-new-object: error,
     no-plusplus: off,
     no-restricted-syntax: error,

src/components/LiveUpdate.jsx

@@ -6,13 +6,14 @@ const { Provider } = UpdateContext;
 
 /**
  * Component that creates an UpdateContext by subscribing
- * to updates of a whitespace-separated list of resources.
+ * to updates of an array (or whitespace-separated string) of resources.
  *
  * Children or descendants that use UpdateContext as a context
  * will be rerendered if any of those resources are updated.
  */
 export default function LiveUpdate({ subscribe = '', children = null }) {
-  const urls = subscribe.trim() ? subscribe.split(/\s+/) : [];
+  const urls = typeof subscribe !== 'string' ? subscribe :
+    (/\S/.test(subscribe) ? subscribe.trim().split(/\s+/) : []);
   const latestUpdate = useLatestUpdate(...urls);
   return <Provider value={latestUpdate}>{children}</Provider>;
 }

test/components/LiveUpdate-test.jsx

@@ -49,11 +49,11 @@ describe('a LiveUpdate component', () => {
     });
   });
 
-  describe('subscribing to two resources', () => {
+  describe('subscribing to two resources with an array', () => {
     beforeAll(() => {
       useLatestUpdate.mockClear();
       ({ container } = render(
-        <LiveUpdate subscribe="https://a.com/1  https://b.com/2">
+        <LiveUpdate subscribe={['https://a.com/1', 'https://b.com/2']}>
           <ShowContext/>
         </LiveUpdate>
       ));
@@ -73,4 +73,20 @@ describe('a LiveUpdate component', () => {
       expect(container.innerHTML).toBe('{"update":true}');
     });
   });
+
+  describe('subscribing to two resources with a string', () => {
+    beforeAll(() => {
+      useLatestUpdate.mockClear();
+      ({ container } = render(
+        <LiveUpdate subscribe=" https://a.com/1  https://b.com/2  ">
+          <ShowContext/>
+        </LiveUpdate>
+      ));
+    });
+
+    it('calls useLatestUpdate with the given resources', () => {
+      expect(useLatestUpdate).toHaveBeenCalledTimes(1);
+      expect(useLatestUpdate).toHaveBeenCalledWith('https://a.com/1', 'https://b.com/2');
+    });
+  });
 });