perf: do not use u flag and cache symbols

.eslintrc.json

@@ -2,6 +2,7 @@
   "root": true,
   "extends": ["plugin:grules/all"],
   "rules": {
-    "no-await-in-loop": "off"
+    "no-await-in-loop": "off",
+    "require-unicode-regexp": "off"
   }
 }

src/html.js

@@ -1,3 +1,9 @@
+const arrayIsArray = Array.isArray;
+
+const symbolIterator = Symbol.iterator;
+
+const symbolAsyncIterator = Symbol.asyncIterator;
+
 const escapeDictionary = {
   '"': """,
   "&": "&",
@@ -7,10 +13,7 @@ const escapeDictionary = {
   "`": "`",
 };
 
-const escapeRegExp = new RegExp(
-  `[${Object.keys(escapeDictionary).join("")}]`,
-  "u",
-);
+const escapeRegExp = new RegExp(`[${Object.keys(escapeDictionary).join("")}]`);
 
 const escapeFunction = (string) => {
   const stringLength = string.length;
@@ -30,8 +33,6 @@ const escapeFunction = (string) => {
   return escaped + string.slice(start, end);
 };
 
-const arrayIsArray = Array.isArray;
-
 /**
  * @param {{ raw: string[] }} literals Tagged template literals.
  * @param {...any} expressions Expressions to interpolate.
@@ -85,7 +86,7 @@ const htmlGenerator = function* ({ raw: literals }, ...expressions) {
     } else if (expression === undefined || expression === null) {
       string = "";
     } else {
-      if (expression[Symbol.iterator]) {
+      if (expression[symbolIterator]) {
         const isRaw =
           literal !== "" && literal.charCodeAt(literal.length - 1) === 33;
 
@@ -105,7 +106,7 @@ const htmlGenerator = function* ({ raw: literals }, ...expressions) {
               continue;
             }
 
-            if (expression[Symbol.iterator]) {
+            if (expression[symbolIterator]) {
               for (expression of expression) {
                 if (typeof expression === "string") {
                   string = expression;
@@ -182,7 +183,7 @@ const htmlAsyncGenerator = async function* ({ raw: literals }, ...expressions) {
     } else if (expression === undefined || expression === null) {
       string = "";
     } else {
-      if (expression[Symbol.iterator] || expression[Symbol.asyncIterator]) {
+      if (expression[symbolIterator] || expression[symbolAsyncIterator]) {
         const isRaw =
           literal !== "" && literal.charCodeAt(literal.length - 1) === 33;
 
@@ -202,10 +203,7 @@ const htmlAsyncGenerator = async function* ({ raw: literals }, ...expressions) {
               continue;
             }
 
-            if (
-              expression[Symbol.iterator] ||
-              expression[Symbol.asyncIterator]
-            ) {
+            if (expression[symbolIterator] || expression[symbolAsyncIterator]) {
               for await (expression of expression) {
                 if (typeof expression === "string") {
                   string = expression;