fix: undefined string when using ucfirst

Author: kobenguyent

lib/utils.js

@@ -94,19 +94,19 @@ module.exports.template = function (template, data) {
 /**
  * Make first char uppercase.
  * @param {string} str
- * @returns {string}
+ * @returns {string | undefined}
  */
 module.exports.ucfirst = function (str) {
-  return str.charAt(0).toUpperCase() + str.substr(1)
+  if (str) return str.charAt(0).toUpperCase() + str.substr(1)
 }
 
 /**
  * Make first char lowercase.
  * @param {string} str
- * @returns {string}
+ * @returns {string | undefined}
  */
 module.exports.lcfirst = function (str) {
-  return str.charAt(0).toLowerCase() + str.substr(1)
+  if (str) return str.charAt(0).toLowerCase() + str.substr(1)
 }
 
 module.exports.chunkArray = function (arr, chunk) {

test/unit/utils_test.js

@@ -38,6 +38,10 @@ describe('utils', () => {
     it('should capitalize first letter', () => {
       expect(utils.ucfirst('hello')).equal('Hello')
     })
+
+    it('should handle the undefined', () => {
+      expect(utils.ucfirst()).to.be.undefined
+    })
   })
 
   describe('#beautify', () => {