How to use Rails 4 strong parameters with has_many :through association?

Question

I\'m having trouble getting a has_many :through association working with Rails 4\'s strong parameters. I have a model called Checkout and I need to select a per

Answer 1

Keep in mind that the name you give to your strong parameters (employees, employee_ids, etc.) is largely irrelevant because it depends on the name you choose to submit. Strong parameters work no "magic" based upon naming conventions.

The reason https://gist.github.com/leemcalilly/a71981da605187d46d96 is throwing an "Unpermitted parameter" error on 'employee_ids' is because it is expecting an array of scalar values, per https://github.com/rails/strong_parameters#nested-parameters, not just a scalar value.

# If instead of:
... "employee_ids" => "1" ...
# You had:
... "employee_ids" => ["1"]

Then your strong parameters would work, specifically:

... { :employee_ids => [] } ...

Because it is receiving an array of scalar values instead of just a scalar value.