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

var obj = {1: false, 2: true /*...*/};

you can use reduce:

_(obj).reduce(function(memo, val, key){
    if (val)
        memo.push(key);
    return memo;
}, []);

or chain map:

_(obj).chain().map(function(val, key){
    if (val)
        return key;
}).reject(_.isUndefined).value();