Assign unique id to js array without changing structure

Question

I have lots of JS arrays like the following:

 q = [{
      "v": "blah",
          "t": "asdfsdf",
 }, {
      "v": "basldfasdfd",
          "t": "blah",
 }...]

I'd like to assign unique id's to them, and then attach those id's to buttons, essentially. However, I'm not sure where I should put the id's without changing the structure of the JS array. I'm building an angular JS app and in the chrome dev tools, I've noticed a $$hashkey for each element. Does the entire array have a property like that? If so, how can I use it, and will it change if the array changes (which it will)?

I'd like to avoid further nesting, ie, I'd prefer to avoid having to do something like

q = {
  data: [whatever was above],
  meta: { id: 234234324, ... }
};

Is that the only way? If so, then in AngularJS, instead of doing ng-repeat="item in q", I would just do ng-repeat="item in q.data", right?

Answer 1

Angular adds $$hashKey to keep track of your changes, so it knows when it needs to update the DOM. (more info)

q = {
  data: [whatever was above],
  meta: { id: 234234324, ... }
}; 

Is that the only way?

I don't see why i would use another structure, this one is good.

If so, then in angularJS, instead of doing ng-repeat="item in q", I would just do ng-repeat="item in q.data", right?

Yes

Answer 2

If I understood your question correctly, you can use lodash's _.indexBy()

It will convert your array to an object that you can call by keys

var q = [{
    "v": "blah",
    "t": "asdfsdf",
}, {
    "v": "basldfasdfd",
    "t": "blah",
}];

// returns an object that has the value of v as the key
console.log(_.indexBy(q, 'v'));

// returns an object that has the value of t as the key
console.log(_.indexBy(q, 't'));

Here's an example: http://jsfiddle.net/wnnr0hza/