Return an object key only if value is true

Question

How do i return an object key name only if the value of it is true?

I\'m using underscore and the only thing i see is how to return keys which is easy, i want to avo

Answer 1

There is another alternative, which could be used with Lodash library using two methods:

• _.pickBy - it creates an object composed of the object properties. If there is no additional parameter (predicate) then all returned properties will have truthy values.
• _.keys(object) - creates an array of keys from the given object

So in your example it would be:

var obj = {1001: true, 1002: false};
var keys = _.keys(_.pickBy(obj));

// keys variable is ["1001"]

Using Underscore.js library, it would be very similar. You need to use _.pick and _.keys functions. The only difference is that _.pick would need to have predicate function, which is _.identity.

So the code would be as follows:

var obj = {1001: true, 1002: false};
var keys = _.keys(_.pick(obj, _.identity));

// keys variable is ["1001"]

I hope that will help