Невозможно обработать дату из firebase в angular 6

 this.qS = this.afDatabase.list('path', ref => {
    return ref.limitToLast(1000);
  }).snapshotChanges().map(changes => {
    return changes.map(c => ({ key1: c.payload.key,value1:c.payload.val() }));
  });
  this.qS.subscribe(values => {
    let count: number = Object.keys((values)).length;
    for(let i=0;i<count;i++){
           let const2:number=Object.keys(values[i].value1).length;  // is 3
           for(let j=0;j<const2;j++){
              console.info( values[i].value1[j]);//this line gives undefined why and How to get value from this?
            }
    }
  });

values ​​[i] .value1 => [объект Object]

JSON.stringify(values[i].value1)=>
    {"-LJ2PhylTGjo1Li6QxP4":{"dtime":{"befor_":0,"dates":"04-Aug-2018","from_t":14,"fullDetails":"Between 2 PM to 6 PM on 7-08-2018","id":1,"mDay":"7","mMonth":"08","mYear":"2018","to_t":18,"weak":2},"lan":0,"lon":0},"-LJ2PtF3X9OaH-5Lv982":{"dtime":{"befor_":0,"dates":"04-Aug-2018","from_t":14,"fullDetails":"Between 2 PM to 6 PM on 7-08-2018","id":1,"mDay":"7","mMonth":"08","mYear":"2018","to_t":18,"weak":2},"lan":0,"lon":0},"-LJIQjbtU7Ryz-gUcxRF":{"dtime":{"befor_":0,"dates":"07-Aug-2018","from_t":14,"fullDetails":"Between 2 PM to 6 PM on 8-08-2018","id":1,"mDay":"8","mMonth":"08","mYear":"2018","timestampCreated":{"timestamp":1533629365655},"to_t":18,"weak":3},"lan":0,"lon":0}}

Теперь нам нужно прочитать дату fullDetails из приведенной выше строки. Как это сделать в машинописном тексте?