Lo-Dash, which extends Underscore, has findIndex method, that can find the index of a given instance, or by a given predicate, or according to the properties of a given object.

In your case, I would do:

var index = _.findIndex(tv, { id: voteID });

Give it a try.

If you need a single index satisfying that condition, you can use findIndex of es6 or lodash

data.findIndex(a=>a.booleanProperty)

If you need all the indexes satisfying your condition, you can either map and filter together sequentially (as shown in ben's answer) or you can merge them to a single reduce to iterate only once and build your index array. here we go:

data.reduce((r, a, i)=> (a.booleanProperty && r.push(i), r), [])

let data = [{"booleanProperty":false},{"booleanProperty":true},{"booleanProperty":false},{"booleanProperty":true},{"booleanProperty":false}];
    
let indexes = data.reduce((r, a, i)=> (a.booleanProperty && r.push(i), r), []);
  
  
console.log(indexes);

Use this instead:

var array = [{'id': 1, 'name': 'xxx'},
             {'id': 2, 'name': 'yyy'},
             {'id': 3, 'name': 'zzz'}];

var searchValue = {'id': 1, 'name': 'xxx'},
    index = -1;

_.each(array, function(data, idx) { 
   if (_.isEqual(data, searchValue)) {
      index = idx;
      return;
   }
});

console.log(index); //0

In your snippet data === searchValue compares the objects' references, you don't want to do this. On the other hand, if you use data == searchValue you are going to compare objects' string representations i.e. [Object object] if you don't have redefined toString methods.

So the correct way to compare the objects is to use _.isEqual.

From Lodash Documentation:

Iterates over elements of collection and invokes iteratee for each element. The iteratee is invoked with three arguments: (value, index|key, collection). Iteratee functions may exit iteration early by explicitly returning false.

_.each gets only one Collection to iterate as the first argument, and a function "iteratee" for the second argument. So, for is a good option for you.

However, if you still want to use lodash you can get help from _range to create an array of indices, and then you can do something like that:

(in javascript of course)

let days = [5, 15, 25];
let hours = [6, 8, 7];
let result = [];
_.each(_.range(days.length),function(i) {
    if (days[i] < a && b < days[i+1]) {
        result.push(hours[i]);
    } else if (days[i] > a && days[i] < b) {
        result.push(hours[i]);
        if (i > 0) {
            result.push(hours[i-1]);
        }
    }
});