what is index a on a javascript object code example

Example: indexof object javascript

var hello = {
    hello: 'world',
    foo: 'bar'
};
var qaz = {
    hello: 'stevie',
    foo: 'baz'
}

var myArray = [];
myArray.push(hello,qaz);

var indexOfStevie = myArray.findIndex(i => i.hello === "stevie");