Code style changes.

- Invert negative connotation of variables for improved readability.
- Return null instead of undefined from validators.
- Extract Jest test component instantiation into beforeEach.

Author: cjcenizal

x-pack/plugins/remote_clusters/public/sections/components/remote_cluster_form/remote_cluster_form.js

@@ -203,7 +203,7 @@ export const RemoteClusterForm = injectI18n(
     hasErrors = () => {
       const { fieldsErrors, localSeedErrors } = this.state;
       const errorValues = Object.values(fieldsErrors);
-      const hasErrors = errorValues.some(error => error !== undefined) || localSeedErrors.length;
+      const hasErrors = errorValues.some(error => error != null) || localSeedErrors.length;
       return hasErrors;
     };
 

x-pack/plugins/remote_clusters/public/sections/components/remote_cluster_form/validators/validate_name.js

@@ -26,5 +26,5 @@ export function validateName(name) {
     );
   }
 
-  return undefined;
+  return null;
 }

x-pack/plugins/remote_clusters/public/sections/components/remote_cluster_form/validators/validate_seed.js

@@ -18,9 +18,9 @@ export function validateSeed(seed) {
     return errors;
   }
 
-  const isInvalid = !isSeedNodeValid(seed);
+  const isValid = isSeedNodeValid(seed);
 
-  if (isInvalid) {
+  if (!isValid) {
     errors.push(i18n.translate(
       'xpack.remoteClusters.remoteClusterForm.localSeedError.invalidCharactersMessage',
       {
@@ -30,9 +30,9 @@ export function validateSeed(seed) {
     ));
   }
 
-  const isPortInvalid = !isSeedNodePortValid(seed);
+  const isPortValid = isSeedNodePortValid(seed);
 
-  if (isPortInvalid) {
+  if (!isPortValid) {
     errors.push(i18n.translate(
       'xpack.remoteClusters.remoteClusterForm.localSeedError.invalidPortMessage',
       {

x-pack/plugins/remote_clusters/public/sections/components/remote_cluster_form/validators/validate_seeds.js

@@ -11,14 +11,14 @@ export function validateSeeds(seeds, seedInput) {
   const seedsHaveBeenCreated = seeds.some(seed => Boolean(seed.trim()));
 
   if (seedsHaveBeenCreated) {
-    return undefined;
+    return null;
   }
 
   // If the user hasn't entered any seeds then we only want to prompt them for some if they
   // aren't already in the process of entering one in. In this case, we'll just show the
   // combobox-specific validation.
   if (seedInput) {
-    return undefined;
+    return null;
   }
 
   return (

x-pack/plugins/remote_clusters/public/sections/components/remote_cluster_form/validators/validate_seeds.test.js

@@ -12,10 +12,10 @@ describe('validateSeeds', () => {
   });
 
   test(`accepts empty seeds when there's input`, () => {
-    expect(validateSeeds([], 'input')).toBe(undefined);
+    expect(validateSeeds([], 'input')).toBe(null);
   });
 
   test(`accepts existing seeds`, () => {
-    expect(validateSeeds(['seed'])).toBe(undefined);
+    expect(validateSeeds(['seed'])).toBe(null);
   });
 });

x-pack/plugins/remote_clusters/public/sections/remote_cluster_list/remote_cluster_table/remote_cluster_table.test.js

@@ -69,32 +69,27 @@ describe('RemoteClusterTable', () => {
       seeds: ['seed'],
     }];
 
-    test('name link opens detail panel when clicked', () => {
-      const component = mountWithIntl(
+    let component;
+
+    beforeEach(() => {
+      component = mountWithIntl(
         <Provider store={remoteClustersStore}>
           <RemoteClusterTable
             clusters={clusters}
             openDetailPanel={() => {}}
           />
         </Provider>
       );
+    });
 
+    test('name link opens detail panel when clicked', () => {
       const rowName = findTestSubject(component, `remoteClusterTableRowName-${name}`);
       rowName.simulate('click');
       const detailPanel = findTestSubject(component, 'remoteClusterDetailFlyout');
       expect(detailPanel).toBeTruthy();
     });
 
     test('remove button displays a confirmation modal when clicked', () => {
-      const component = mountWithIntl(
-        <Provider store={remoteClustersStore}>
-          <RemoteClusterTable
-            clusters={clusters}
-            openDetailPanel={() => {}}
-          />
-        </Provider>
-      );
-
       const removeButton = findTestSubject(component, `remoteClusterTableRowRemoveButton-${name}`);
       removeButton.simulate('click');
       const confirmModal = findTestSubject(component, 'remoteClustersDeleteConfirmModal');