find the array index of an object with a specific key value in underscore

Question

In underscore, I can successfully find an item with a specific key value

var tv = [{id:1},{id:2}]
var voteID = 2;
var data = _.find(tv, function(voteItem){ r         


        

Answer 1

Keepin' it simple:

// Find the index of the first element in array
// meeting specified condition.
//
var findIndex = function(arr, cond) {
  var i, x;
  for (i in arr) {
    x = arr[i];
    if (cond(x)) return parseInt(i);
  }
};

var idIsTwo = function(x) { return x.id == 2 }
var tv = [ {id: 1}, {id: 2} ]
var i = findIndex(tv, idIsTwo) // 1

Or, for non-haters, the CoffeeScript variant:

findIndex = (arr, cond) ->
  for i, x of arr
    return parseInt(i) if cond(x)