From e7f7e89d96b2aa6e250dba05bedee78dfd38de17 Mon Sep 17 00:00:00 2001
From: Harry Mills <harry@portermills.net>
Date: Wed, 28 Aug 2019 14:23:30 -0400
Subject: [PATCH] [fix] `jsx-pascal-case`: allow one-letter-named components

Fixes #2394.

$ and _ are valid names for components that are neither upper nor lower
case. This change ensures the pascal case rule doesn't apply to single letter components
---
 lib/rules/jsx-pascal-case.js       | 1 +
 tests/lib/rules/jsx-pascal-case.js | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/rules/jsx-pascal-case.js b/lib/rules/jsx-pascal-case.js
index 268755c2e1..fb8ea45427 100644
--- a/lib/rules/jsx-pascal-case.js
+++ b/lib/rules/jsx-pascal-case.js
@@ -51,6 +51,7 @@ module.exports = {
     return {
       JSXOpeningElement(node) {
         let name = elementType(node);
+        if (name.length === 1) return undefined;
 
         // Get namespace if the type is JSXNamespacedName or JSXMemberExpression
         if (name.indexOf(':') > -1) {
diff --git a/tests/lib/rules/jsx-pascal-case.js b/tests/lib/rules/jsx-pascal-case.js
index 0a17cd4ef8..f0965730f2 100644
--- a/tests/lib/rules/jsx-pascal-case.js
+++ b/tests/lib/rules/jsx-pascal-case.js
@@ -59,6 +59,12 @@ ruleTester.run('jsx-pascal-case', rule, {
   }, {
     code: '<IGNORED />',
     options: [{ignore: ['IGNORED']}]
+  }, {
+    code: '<T />'
+  }, {
+    code: '<$ />'
+  }, {
+    code: '<_ />'
   }],
 
   invalid: [{
@@ -82,5 +88,8 @@ ruleTester.run('jsx-pascal-case', rule, {
     code: '<__ />',
     options: [{allowAllCaps: true}],
     errors: [{message: 'Imported JSX component __ must be in PascalCase or SCREAMING_SNAKE_CASE'}]
+  }, {
+    code: '<$a />',
+    errors: [{message: 'Imported JSX component $a must be in PascalCase'}]
   }]
 });