diff --git a/lib/utils/casing.js b/lib/utils/casing.js
index 741481ef8..719e80544 100644
--- a/lib/utils/casing.js
+++ b/lib/utils/casing.js
@@ -1,6 +1,25 @@
 const assert = require('assert')
 
-const invalidChars = /[^a-zA-Z0-9:]+/g
+function parseWords (str) {
+  return str
+    .normalize()
+    .replace(/[\-!#$%^&*()_+~`"'<>,./?\[\]{}\s\r\n\v\t]+/gu, ' ')
+    .split(/([A-Z\s][^A-Z\s]*)/gu)
+    .map(word => word.trim())
+    .filter(Boolean)
+}
+
+function toLowerCase (str) {
+  return str.replace(/[A-Z]/gu, (l) => l.toLowerCase())
+}
+
+function toUpperCase (str) {
+  return str.replace(/[a-z]/gu, (l) => l.toUpperCase())
+}
+
+function capitalizeFirstLetter (str) {
+  return toUpperCase(str[0]) + str.slice(1)
+}
 
 /**
  * Convert text to kebab-case
@@ -8,12 +27,7 @@ const invalidChars = /[^a-zA-Z0-9:]+/g
  * @return {string}
  */
 function kebabCase (str) {
-  return str
-    .replace(/[A-Z]/g, match => '-' + match)
-    .replace(/([^a-zA-Z])-([A-Z])/g, match => match[0] + match[2])
-    .replace(/^-/, '')
-    .replace(invalidChars, '-')
-    .toLowerCase()
+  return toLowerCase(parseWords(str).join('-'))
 }
 
 /**
@@ -22,12 +36,7 @@ function kebabCase (str) {
  * @return {string}
  */
 function snakeCase (str) {
-  return str
-    .replace(/[A-Z]/g, match => '_' + match)
-    .replace(/([^a-zA-Z])_([A-Z])/g, match => match[0] + match[2])
-    .replace(/^_/, '')
-    .replace(invalidChars, '_')
-    .toLowerCase()
+  return toLowerCase(parseWords(str).join('_'))
 }
 
 /**
@@ -36,12 +45,9 @@ function snakeCase (str) {
  * @return {string} Converted string
  */
 function camelCase (str) {
-  return str
-    .replace(/_/g, (_, index) => index === 0 ? _ : '-')
-    .replace(/(?:^\w|[A-Z]|\b\w)/g, (letter, index) =>
-      index === 0 ? letter.toLowerCase() : letter.toUpperCase()
-    )
-    .replace(invalidChars, '')
+  return parseWords(str)
+    .map((word, index) => index === 0 ? toLowerCase(word) : capitalizeFirstLetter(word))
+    .join('')
 }
 
 /**
@@ -50,10 +56,9 @@ function camelCase (str) {
  * @return {string} Converted string
  */
 function pascalCase (str) {
-  return str
-    .replace(/_/g, (_, index) => index === 0 ? _ : '-')
-    .replace(/(?:^\w|[A-Z]|\b\w)/g, (letter, index) => letter.toUpperCase())
-    .replace(invalidChars, '')
+  return parseWords(str)
+    .map((word) => capitalizeFirstLetter(word))
+    .join('')
 }
 
 const convertersMap = {
diff --git a/tests/lib/rules/prop-name-casing.js b/tests/lib/rules/prop-name-casing.js
index 842e07ab8..1dd961079 100644
--- a/tests/lib/rules/prop-name-casing.js
+++ b/tests/lib/rules/prop-name-casing.js
@@ -287,6 +287,30 @@ ruleTester.run('prop-name-casing', rule, {
         }
       `,
       parserOptions
+    },
+    {
+      // Japanese characters
+      filename: 'test.vue',
+      code: `
+        export default {
+          props: {
+            '漢字': String
+          }
+        }
+      `,
+      parserOptions
+    },
+    {
+      // emoji
+      filename: 'test.vue',
+      code: `
+        export default {
+          props: {
+            '\u{1F37B}': String
+          }
+        }
+      `,
+      parserOptions
     }
   ],
 
@@ -489,42 +513,6 @@ ruleTester.run('prop-name-casing', rule, {
         line: 4
       }]
     },
-    {
-      // emoji
-      filename: 'test.vue',
-      code: `
-        export default {
-          props: {
-            '\u{1F37B}': String
-          }
-        }
-      `,
-      output: null,
-      parserOptions,
-      errors: [{
-        message: 'Prop "\u{1F37B}" is not in camelCase.',
-        type: 'Property',
-        line: 4
-      }]
-    },
-    {
-      // Japanese characters
-      filename: 'test.vue',
-      code: `
-        export default {
-          props: {
-            '漢字': String
-          }
-        }
-      `,
-      output: null,
-      parserOptions,
-      errors: [{
-        message: 'Prop "漢字" is not in camelCase.',
-        type: 'Property',
-        line: 4
-      }]
-    },
     {
       filename: 'test.vue',
       code: `
diff --git a/tests/lib/utils/casing.js b/tests/lib/utils/casing.js
index d72d186d5..81014d6eb 100644
--- a/tests/lib/utils/casing.js
+++ b/tests/lib/utils/casing.js
@@ -9,6 +9,7 @@ describe('getConverter()', () => {
   it('should convert string to camelCase', () => {
     const converter = casing.getConverter('camelCase')
 
+    assert.equal(converter('foo'), 'foo')
     assert.equal(converter('fooBar'), 'fooBar')
     assert.equal(converter('foo-bar'), 'fooBar')
     assert.equal(converter('foo_bar'), 'fooBar')
@@ -17,11 +18,18 @@ describe('getConverter()', () => {
     assert.equal(converter('FooBAR'), 'fooBAR')
     assert.equal(converter('Foo1BAZ'), 'foo1BAZ')
     assert.equal(converter('foo1b_a_z'), 'foo1bAZ')
+    assert.equal(converter('darИībaÊÊw'), 'darИībaÊÊw')
+    assert.equal(converter('klâwen-ûf'), 'klâwenûf')
+    assert.equal(converter('пустынныхИвдалП'), 'пустынныхИвдалП')
+    assert.equal(converter('kpłĄżć'), 'kpłĄżć')
+    assert.equal(converter('ÊtreSîne'), 'ÊtreSîne')
+    assert.equal(converter('    foo       Bar   '), 'fooBar')
   })
 
   it('should convert string to PascalCase', () => {
     const converter = casing.getConverter('PascalCase')
 
+    assert.equal(converter('foo'), 'Foo')
     assert.equal(converter('fooBar'), 'FooBar')
     assert.equal(converter('foo-bar'), 'FooBar')
     assert.equal(converter('foo_bar'), 'FooBar')
@@ -30,30 +38,50 @@ describe('getConverter()', () => {
     assert.equal(converter('FooBAR'), 'FooBAR')
     assert.equal(converter('Foo1BAZ'), 'Foo1BAZ')
     assert.equal(converter('foo1b_a_z'), 'Foo1bAZ')
+    assert.equal(converter('darИībaÊÊw'), 'DarИībaÊÊw')
+    assert.equal(converter('klâwen-ûf'), 'Klâwenûf')
+    assert.equal(converter('пустынныхИвдалП'), 'пустынныхИвдалП')
+    assert.equal(converter('kpłĄżć'), 'KpłĄżć')
+    assert.equal(converter('ÊtreSîne'), 'ÊtreSîne')
+    assert.equal(converter('    foo       Bar   '), 'FooBar')
   })
 
   it('should convert string to kebab-case', () => {
     const converter = casing.getConverter('kebab-case')
 
+    assert.equal(converter('foo'), 'foo')
     assert.equal(converter('fooBar'), 'foo-bar')
     assert.equal(converter('foo-bar'), 'foo-bar')
     assert.equal(converter('foo_bar'), 'foo-bar')
     assert.equal(converter('FooBar'), 'foo-bar')
-    assert.equal(converter('Foo1Bar'), 'foo1bar')
+    assert.equal(converter('Foo1Bar'), 'foo1-bar')
     assert.equal(converter('FooBAR'), 'foo-b-a-r')
-    assert.equal(converter('Foo1BAZ'), 'foo1b-a-z')
+    assert.equal(converter('Foo1BAZ'), 'foo1-b-a-z')
     assert.equal(converter('foo1b_a_z'), 'foo1b-a-z')
+    assert.equal(converter('darИībaÊÊw'), 'darИībaÊÊw')
+    assert.equal(converter('klâwen-ûf'), 'klâwen-ûf')
+    assert.equal(converter('пустынныхИвдалП'), 'пустынныхИвдалП')
+    assert.equal(converter('kpłĄżć'), 'kpłĄżć')
+    assert.equal(converter('ÊtreSîne'), 'Être-sîne')
+    assert.equal(converter('    foo       Bar   '), 'foo-bar')
   })
 
   it('should convert string to snake_case', () => {
     const converter = casing.getConverter('snake_case')
 
+    assert.equal(converter('a'), 'a')
     assert.equal(converter('fooBar'), 'foo_bar')
     assert.equal(converter('foo-bar'), 'foo_bar')
     assert.equal(converter('FooBar'), 'foo_bar')
-    assert.equal(converter('Foo1Bar'), 'foo1bar')
+    assert.equal(converter('Foo1Bar'), 'foo1_bar')
     assert.equal(converter('FooBAR'), 'foo_b_a_r')
-    assert.equal(converter('Foo1BAZ'), 'foo1b_a_z')
+    assert.equal(converter('Foo1BAZ'), 'foo1_b_a_z')
     assert.equal(converter('foo1b_a_z'), 'foo1b_a_z')
+    assert.equal(converter('darИībaÊÊw'), 'darИībaÊÊw')
+    assert.equal(converter('klâwen-ûf'), 'klâwen_ûf')
+    assert.equal(converter('пустынныхИвдалП'), 'пустынныхИвдалП')
+    assert.equal(converter('kpłĄżć'), 'kpłĄżć')
+    assert.equal(converter('ÊtreSîne'), 'Être_sîne')
+    assert.equal(converter('    foo       Bar   '), 'foo_bar')
   })
 })