Get object keys for filtered values

Question

The case is simple - I\'ve got a following object:

Object {1: false, 2: true, 3: false, 4: false, 5: false, 6: false, 7: false, 8: true, 12: false, 13: false, 14         


        

Answer 1

Another potential solution:

// Your example data
var data = {1: false, 2: true, 3: false, 4: false, 5: false, 6: false, 7: false, 8: true, 12: false, 13: false, 14: false, 15: false, 16: false, 17: false, 18: false, 19: false};

// Outputs the keys: ["2", "8"]
_.keys(_.transform(data, function(r, v, k) { v ? r[k] = 1 : null; }));

// Outputs the keys as integers: [2, 8]
_.map(_.keys(_.transform(data, function(r, v, k) { v ? r[k] = 1 : null; })), _.parseInt)

So basically:

1. Transform the original object to strip out the false-valued keys
2. Grab the list of keys from the transformed result
3. Convert the keys to ints if you need to