Question

why does the following indexOf(searchElement:T, fromIndex:int = 0):int not find the object and return -1?

var v:Vector.<Object> = new Vector.<Object>();
v.push({name:"Geoffrey", age:32});

trace(v.indexOf({name:"Geoffrey", age:32}));

Answer 1

Simple answer is that Vector.indexOf() searches by reference. In your code you have created two, completely separate objects; they may look identical to you, but that’s because you’re a human 🙂

const v : Vector.<Object> = new Vector.<Object>();
const geoff : Object = { name: "Geoffrey", age: 32 };

v.push(geoff);
const index : uint = v.indexOf(geoff);

trace("Geoff is at index: " + index);  // Traces "Geoff is at index: 0".

If you want to find the index of an object based on its properties you will want to use a fori loop.

const people : Vector.<Object> = new Vector.<Object>();
people.push({ name: "Jonny", age: 28 });
people.push({ name: "Geoffrey", age: 32 });

const needle : String = "Geoffrey";

var index : int = -1;
for (var i : uint = 0; i < people.length; i++) {
    if (people[i].name == needle) {
        index = i;
        break;
    }
}

trace(needle + " found at index: " + index);