When the regex.test function is not functioning correctly in a Vue.js JavaScript router, issues may arise

Question

When the regex.test function is not functioning correctly in a Vue.js JavaScript router, issues may arise

const router = createRouter({
  history: createWebHistory(),
  routes,
});

// ...

const allowedToAnonymous = [
  /^\/login$/g,
  /^\/signup$/g,
  /^\/home$/g,
  /^\/emailconfirm\/[0-9a-zA-Z]{8}$/g,
  /^\/serviceGuide$/g,
  /^\/$/g
];

router.beforeEach((to, from) => {
  for (var regex of allowedToAnonymous) {
    console.log(regex);
    console.log(to.path);
    if (regex.test(to.path)) {
      console.log('return');
      return;
    } else {
      console.log(regex.test(to.path));
      console.log('do not return');
    }
  }

  const checkLogin = stores.getters['userStore/checkLogin'];
  if (!checkLogin) return '/login';
});

I implemented this code in my Vue.js project. It directs users to the login page if certain regular expressions do not match the current path and they are not logged in. All console.log statements are for debugging purposes. When testing in a web browser, I observed the following behavior:

/^\/login$/g
/serviceGuide
false
do not return
/^\/signup$/g
/serviceGuide
false
do not return
/^\/home$/g
/serviceGuide
false
do not return
/^\/emailconfirm\/[0-9a-zA-Z]{8}$/g
/serviceGuide
false
do not return
/^\/serviceGuide$/g
/serviceGuide
true
do not return
/^\/$/g
/serviceGuide
false
do not return
/^\/login$/g
/login
return

Pay attention to the output near /^\/serviceGuide$/g. Even when regex.test returns true, it seems to follow the do not return path. This inconsistency occurs after browsing the website multiple times, typically 2 to 4 instances.

What could be causing this issue and how can it be resolved?

javascript regex vue.js vuejs3

Answer 1

Answer №1

Inconsistent behavior may occur if regexes are saved between multiple navigations. Consider the following example:

let regex = /^\/serviceGuide$/g
console.log(regex.test('/serviceGuide')); // true
console.log(regex.test('/serviceGuide')); // false
console.log(regex.test('/serviceGuide')); // true
console.log(regex.test('/serviceGuide')); // false
console.log(regex.test('/serviceGuide')); // true

The issue here is caused by the /g flag in the regex - it searches for subsequent matches after the first one. Removing this flag will resolve the problem and allow it to match from the beginning.

The observed behavior occurs because you enter the function after a successful match. As a result, the first regex.test call inside the function returns false, followed by a true response.

To summarize: eliminate the /g flag.

Answer 2

Inconsistent behavior may occur if regexes are saved between multiple navigations. Consider the following example:

let regex = /^\/serviceGuide$/g
console.log(regex.test('/serviceGuide')); // true
console.log(regex.test('/serviceGuide')); // false
console.log(regex.test('/serviceGuide')); // true
console.log(regex.test('/serviceGuide')); // false
console.log(regex.test('/serviceGuide')); // true

The issue here is caused by the /g flag in the regex - it searches for subsequent matches after the first one. Removing this flag will resolve the problem and allow it to match from the beginning.

The observed behavior occurs because you enter the function after a successful match. As a result, the first regex.test call inside the function returns false, followed by a true response.

To summarize: eliminate the /g flag.

When the regex.test function is not functioning correctly in a Vue.js JavaScript router, issues may arise

Answer №1

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