JSFiddle - React, Tailwind, and code Playground

JavaScript

var json = [{
    id: 1,
    total: 50.00
}, {
    id: 2,
    total: 70.00
}];
alert(json[1].total);
for (var i = 0; i < json.length; i++) {
    var obj = json[i];
    if (obj.id == 2) {
        obj.total = 100;
        break;
    }
}
alert(json[1].total);