index.js

const trips = [
    {to:'Brazil',distance:1000},
    {to:'Chine',distance: 2500},
    {to:'India',distance: 3000}
 ]
 const initialValue = 0;
 const sumWithInitial = trips.reduce(
   (previousValue, currentValue) => previousValue += currentValue.distance,
   initialValue
 );
 
 console.log(sumWithInitial);