[Vuejs]-Odd behavior for array[value]

First of all Array values can be accessed using index number.

getClanMemberInfo() {
  this.clanMemberInfo = [];
  console.log(this.clan.members);
  console.log(this.clan.officers);
  for (var i = 0; i < this.clan.members.length; i++) {
    firebase
      .firestore()
      .collection("profiles")
      .doc(this.clan.members[i])
      .get()
      .then(profile => {
        var info = profile.data();
        // you are looping using members length so use members below with index
        console.log(this.clan.members[i])
        // you can check if your member is an officer or not by below line
        if (this.clan.officers.includes(this.clan.members[i])) {
          console.log("Hi officer");
          info.officer = true;
        } else {
          console.log("BAT");
          info.officer = false;
        }
        this.clanMemberInfo.push(info);
      });
  }
}

it seems to be this.clan.officers is an array of strings, not a dictionary.

so this.clan.officers[0] is defined as ‘sJUZKKhLDvPDBWPILdzCN9waFpb2’

but this.clan.officers[‘sJUZKKhLDvPDBWPILdzCN9waFpb2’] is pure gibberish.

If you want to check if a given string exists inside an array of values, you can use Array.prototype.includes().

isOfficer = officers.includes('sJUZKKhLDvPDBWPILdzCN9waFpb2');