fix surrogate pair check in js

src/chatUtils.test.ts

@@ -70,9 +70,15 @@ test('isAllowedChatCharacter', () => {
   expect(isAllowedChatCharacter('a')).toBe(true)
   expect(isAllowedChatCharacter('§')).toBe(false)
   expect(isAllowedChatCharacter(' ')).toBe(true)
-  expect(isAllowedChatCharacter('ツ')).toBe(true)
-  expect(isStringAllowed('🟢')).toMatchObject({
+  expect(isStringAllowed('a§b')).toMatchObject({
+    valid: false,
+    clean: 'ab',
+    invalid: ['§']
+  })
+  expect(isStringAllowed('aツ')).toMatchObject({
+    valid: true,
+  })
+  expect(isStringAllowed('a🟢')).toMatchObject({
     valid: true,
-    invalid: null
   })
 })

src/chatUtils.ts

@@ -137,14 +137,24 @@ export function isAllowedChatCharacter (char: string): boolean {
 
 export const isStringAllowed = (str: string) => {
   const invalidChars = new Set<string>()
-  for (const char of str) {
+  for (const [i, char] of [...str].entries()) {
+    const isSurrogatePair = str.codePointAt(i) !== str['charCodeAt'](i)
+    if (isSurrogatePair) continue
+
     if (!isAllowedChatCharacter(char)) {
       invalidChars.add(char)
     }
   }
 
+  const valid = invalidChars.size === 0
+  if (valid) {
+    return {
+      valid: true
+    }
+  }
+
   return {
-    valid: invalidChars.size === 0,
+    valid,
     clean: [...str].filter(c => !invalidChars.has(c)).join(''),
     invalid: [...invalidChars]
   }