test.js

// function distance(lat1, lon1, lat2, lon2) {
//     var R = 6371; // km (change this constant to get miles)
//     var dLat = (lat2 - lat1) * Math.PI / 180;
//     var dLon = (lon2 - lon1) * Math.PI / 180;
//     var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
//         Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) *
//         Math.sin(dLon / 2) * Math.sin(dLon / 2);
//     var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
//     var d = R * c;
//     if (d > 1) return Math.round(d) + "km";
//     else if (d <= 1) return Math.round(d * 1000) + "m";
//     return d;
// }

// console.log(distance(47.44534, -122.29181, 47.61016, -122.34651))



let arr = [{ 'name': 'blue' }, { 'name': 'blue' }]

arr.forEach((ele, i) => {
    if (i == 1) {
        ele['name'] = 'red'
    }
})

console.log(arr)