FIX Don't split ID into separate digits (#335)

client/src/components/LinkField/LinkField.js

@@ -135,12 +135,10 @@ const LinkField = ({
     })
   );
 
-  // The value for a has_one LinkField will start off as a numeric 0
-  // If a parent object containing a child LinkField without a value is submitted,
-  // using FormSchema, then the FormSchema response may contain a string '0' instead
-  // Ensure that a numeric 0 is used
-  if (value === '0') {
-    value = 0;
+  // Sometimes, the value will be given as a numeric string.
+  // Ensure that an actual number is used
+  if (typeof value === 'string') {
+    value = Number(value);
   }
 
   // Ensure we have a valid array

client/src/components/LinkField/tests/LinkField-test.js

@@ -94,6 +94,22 @@ test('LinkField can handle a string "0" value', async () => {
   expect(container.querySelectorAll('.link-picker')).toHaveLength(1);
 });
 
+test('LinkField can handle a multi-digit string value', async () => {
+  const { container } = render(<LinkField {...makeProps({
+    value: '123'
+  })}
+  />);
+
+  await doResolve({ json: () => ({
+    123: {
+      title: 'Page title',
+      typeKey: 'sitetree',
+    },
+  }) });
+  await screen.findByText('Page title');
+  expect(container.querySelectorAll('.link-picker__button')).toHaveLength(1);
+});
+
 test('LinkField will render disabled state if disabled is true', async () => {
   const { container } = render(<LinkField {...makeProps({
     ownerID: 1,