How does this javascript variable exactly work? (Exluding personal info from the URL)

Question

I'm planning to use a javascript variable to replace certain keywords (pii:s) from the URL before sending it from GTM to GA4.

I have encountered a javascript variable that replaces certain "banned" keywords from the query string. I don't know javascript very well myself.

This variable seems to work when I test it (it replaces the values of the banned keywords). However, it does not replace the value of email, unless the value is a real email address. I can't read javascript, but is this what the variable "piiRegex" does?

Does the code look OK overall?

See the code below:

function(){
    var q = {{URL Query}};

    // Add the PII patterns into this array as objects
    var piiRegex = [{
      name: 'EMAIL',
      regex: RegExp(/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/, 'gi'),
            }
    ];
    
    var bannedKeywords = [
      'email',
      'username',
      'password',
      'login',
      'order',
      'transaction',
      'telephone',
      'phone',
      'card',
      'registration',
      'unsubscribe',
      'subscribe',
      'firstname',
      'name',
      'personal_email_verify',
      'personal_lastname',
      'secret',
      'kco',
      'token',
    ];

    var queries = q.split('&');
    for (i = 0; i < queries.length; i++) {
      parts = queries[i].split('=');
      // Double-decode, to account for web server encode + analytics.js encode
      try {
        key = decodeURIComponent(decodeURIComponent(parts[0]));
        val = decodeURIComponent(decodeURIComponent(parts[1]));
      } catch(e) {
        key = decodeURIComponent(parts[0]);
        val = decodeURIComponent(parts[1]);
      }
      piiRegex.forEach(function(pii) {
        val = val.replace(pii.regex, '[CENSORED_' + pii.name + ']');
      });
      
      if (bannedKeywords.indexOf(key) > 0) {
        val = '[CENSORED_' + key + ']';
      }
      parts[1] = encodeURIComponent(val);
      queries[i] = parts.join('=');
    }

    if (q != ''){
     q = '?' + queries.join('&');
    }

 return q;
}