Progress with PR review

- Remove no longer needed variable.
-  Handle edge case where a component is registered using kebab-case but later on is used using PascalCase. e.g: registered as `foo-bar` and used as `FooBar` is not valid.
- Handle edge case `<component is />`, where `node.value` would be `null`. See https://github.com/mysticatea/vue-eslint-parser/blob/master/docs/ast.md#vattribute
- Add more tests to prove all these changes

Author: jesusgn90

Diff for: lib/rules/no-unregistered-components.js

@@ -97,18 +97,30 @@ module.exports = {
         }
       },
       "VAttribute[directive=false][key.name='is']" (node) {
-        if (utils.isHtmlWellKnownElementName(node.value.value)) return
+        if (
+          !node.value || // `<component is />`
+          utils.isHtmlWellKnownElementName(node.value.value)
+        ) return
         usedComponentNodes.push({ node, name: node.value.value })
       },
       "VElement[name='template']" (rootNode) {
         templateLocation = templateLocation || rootNode.loc.start
       },
-      "VElement[name='template']:exit" (rootNode) {
-        const registeredComponentNames = registeredComponents.map(({ name }) => casing.kebabCase(name))
+      "VElement[name='template']:exit" () {
+        // All registered components, transformed to kebab-case
+        const registeredComponentNames = registeredComponents
+          .map(({ name }) => casing.kebabCase(name))
+
+        // All registered components using kebab-case syntax
+        const componentsRegisteredAsKebabCase = registeredComponents
+          .filter(({ name }) => name === casing.kebabCase(name))
+          .map(({ name }) => name)
 
         usedComponentNodes
           .filter(({ name }) => {
             const kebabCaseName = casing.kebabCase(name)
+
+            // Check ignored patterns in first place
             if (ignorePatterns.find(pattern => {
               const regExp = new RegExp(pattern)
               return regExp.test(kebabCaseName) ||
@@ -117,6 +129,17 @@ module.exports = {
                 regExp.test(casing.snakeCase(name)) ||
                 regExp.test(name)
             })) return false
+
+            // Component registered as `foo-bar` cannot be used as `FooBar`
+            if (
+              name.indexOf('-') === -1 &&
+              name === casing.pascalCase(name) &&
+              componentsRegisteredAsKebabCase.indexOf(kebabCaseName) !== -1
+            ) {
+              return true
+            }
+
+            // Otherwise
             return registeredComponentNames.indexOf(kebabCaseName) === -1
           })
           .forEach(({ node, name }) => context.report({

Diff for: tests/lib/rules/no-unregistered-components.js

@@ -324,21 +324,6 @@ tester.run('no-unregistered-components', rule, {
         </script>
       `
     },
-    {
-      filename: 'test.vue',
-      code: `
-        <template>
-          <CustomComponent />
-        </template>
-        <script>
-        export default {
-          components: {
-            'custom-component': InfoPrimaryWrapper
-          }
-        }
-        </script>
-      `
-    },
     {
       filename: 'test.vue',
       code: `
@@ -378,6 +363,37 @@ tester.run('no-unregistered-components', rule, {
           </slot>
         </template>
       `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <Custom-Component />
+        </template>
+        <script>
+        export default {
+          components: {
+            'custom-component': InfoPrimaryWrapper
+          }
+        }
+        </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <component is />
+        </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <Component is />
+        </template>
+      `
     }
   ],
   invalid: [
@@ -526,6 +542,25 @@ tester.run('no-unregistered-components', rule, {
         message: 'The "CustomComponent" component has been used but not registered.',
         line: 3
       }]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <CustomComponent />
+        </template>
+        <script>
+        export default {
+          components: {
+            'custom-component': InfoPrimaryWrapper
+          }
+        }
+        </script>
+      `,
+      errors: [{
+        message: 'The "CustomComponent" component has been used but not registered.',
+        line: 3
+      }]
     }
   ]
 })