From fb6aa97bc25e00abeb32494209e30fe88bfe51ec Mon Sep 17 00:00:00 2001
From: John Otander <johnotander@gmail.com>
Date: Thu, 11 Jul 2019 10:03:05 -0600
Subject: [PATCH] Add param case tests, follow up for #624

---
 packages/mdx/mdx-hast-to-jsx.js |  8 +-------
 packages/mdx/test/util.test.js  | 14 ++++++++++++++
 packages/mdx/util.js            |  7 +++++++
 3 files changed, 22 insertions(+), 7 deletions(-)
 create mode 100644 packages/mdx/test/util.test.js

diff --git a/packages/mdx/mdx-hast-to-jsx.js b/packages/mdx/mdx-hast-to-jsx.js
index de8ccaa80..edfc7e7e5 100644
--- a/packages/mdx/mdx-hast-to-jsx.js
+++ b/packages/mdx/mdx-hast-to-jsx.js
@@ -3,16 +3,10 @@ const declare = require('@babel/helper-plugin-utils').declare
 const {types: t} = require('@babel/core')
 const toStyleObject = require('to-style').object
 const uniq = require('lodash.uniq')
-const {toTemplateLiteral} = require('./util')
+const {paramCase, toTemplateLiteral} = require('./util')
 
 const STARTS_WITH_CAPITAL_LETTER = /^[A-Z]/
 
-const paramCase = string =>
-  string
-    .replace(/([a-z0-9])([A-Z])/g, '$1-$2')
-    .replace(/([a-z])([0-9])/g, '$1-$2')
-    .toLowerCase()
-
 class BabelPluginExtractJsxNames {
   constructor() {
     const names = []
diff --git a/packages/mdx/test/util.test.js b/packages/mdx/test/util.test.js
new file mode 100644
index 000000000..e83504f89
--- /dev/null
+++ b/packages/mdx/test/util.test.js
@@ -0,0 +1,14 @@
+const {paramCase} = require('../util')
+
+const PARAM_CASE_FIXTURES = [
+  ['ariaHidden', 'aria-hidden'],
+  ['data123', 'data-123']
+]
+
+PARAM_CASE_FIXTURES.forEach(([input, expected]) => {
+  test(`it turns ${input} into ${expected}`, () => {
+    const result = paramCase(input)
+
+    expect(result).toEqual(expected)
+  })
+})
diff --git a/packages/mdx/util.js b/packages/mdx/util.js
index f78974d0d..70b767803 100644
--- a/packages/mdx/util.js
+++ b/packages/mdx/util.js
@@ -4,6 +4,12 @@ const EXPORT_DEFAULT_REGEX = /^export default/
 const BLOCKS_REGEX = '[a-z\\.]+(\\.){0,1}[a-z\\.]'
 const EMPTY_NEWLINE = '\n\n'
 
+const paramCase = string =>
+  string
+    .replace(/([a-z0-9])([A-Z])/g, '$1-$2')
+    .replace(/([a-z])([0-9])/g, '$1-$2')
+    .toLowerCase()
+
 const toTemplateLiteral = text => {
   const escaped = text
     .replace(/\\/g, '\\\\') // Escape all "\" to avoid unwanted escaping in text nodes
@@ -18,4 +24,5 @@ module.exports.BLOCKS_REGEX = BLOCKS_REGEX
 module.exports.isImport = text => IMPORT_REGEX.test(text)
 module.exports.isExport = text => EXPORT_REGEX.test(text)
 module.exports.isExportDefault = text => EXPORT_DEFAULT_REGEX.test(text)
+module.exports.paramCase = paramCase
 module.exports.toTemplateLiteral = toTemplateLiteral