Fixed doc

Author: ota-meshi

docs/.vuepress/config.js

@@ -16,7 +16,13 @@ module.exports = {
     serviceWorker: true,
     evergreen: true,
     configureWebpack(_config, _isServer) {
-        return {}
+        return {
+            resolve: {
+                alias: {
+                    eslint: require.resolve("eslint4b"),
+                },
+            },
+        }
     },
 
     head: [

lib/configs/recommended.ts

@@ -10,7 +10,7 @@ export = {
         "no-regex-spaces": "error",
         "prefer-regex-literals": "error",
         // If ESLint is 7 or higher, use core rule. If it is 6 or less, use the copied rule.
-        [parseInt(eslint.Linter.version[0], 10) >= 7
+        [parseInt(eslint.Linter?.version?.[0] ?? "6", 10) >= 7
             ? "no-useless-backreference"
             : "regexp/no-useless-backreference"]: "error",
 

tools/update-rulesets.ts

@@ -24,7 +24,7 @@ export = {
         // ESLint core rules
         ${coreRules.map((ruleName) => `"${ruleName}": "error"`).join(",\n")},
         // If ESLint is 7 or higher, use core rule. If it is 6 or less, use the copied rule.
-        [parseInt(eslint.Linter.version[0], 10) >= 7
+        [parseInt(eslint.Linter?.version?.[0] ?? "6", 10) >= 7
             ? "no-useless-backreference"
             : "regexp/no-useless-backreference"]: "error",