javascript - Firebase does multiple calls even with if/else statement JS -


i building app vue , firebase. new firebase , i've problems it. try store names + emails in database. want check first if email in database , if not, run function store name + email. if email stored in database output alert , cancel submit.

so check of email in database going quite well, output alert, , able retrieve data. problem lays when enter email not in database. when enter new email (and name) check database , return false right away call (i dont know why, that's problem guess) , return true, , alert of being there, @ same time. proceed function store data because output of first call (which false).

my js code:

checkform() {          let app = this;          if (this.name == '' || this.emailadress == '') {             alert('you have fill out form');         } else {              app.getfirebase();          } },  getfirebase() {          let app = this;          var ref = firebase.database().ref().child('/aanmeldingen/');         ref.on('value', function(snapshot) {              const array = [];              snapshot.foreach(function(childsnapshot) {               var checkemail = childsnapshot.val().email;               array.push(checkemail);             });              const res = array.includes(app.emailadress);             console.log(array);             console.log(res);                if(res) {                 alert('you have entered giveaway');               } else if (res == false) {                  app.store();                }         }); },  store() {                 this.step_two = false;                 this.active_two = false;                  this.active_three = true;                 this.step_three = true;                  let app = this;                  firebase.database().ref('/aanmeldingen/').push({                 username: app.name,                 email: app.emailadress,                 }); }

screenshot of console (entered jane, not in database)

enter image description here

you should using once() instead of on(). on() leaves listener attached, when push data in store() listener fires again.


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