[RUBY] If the parameter is an array, how to include it in Stopara's params.permit

If the parameter is an array, how to include it in Stopara's params.permit


I sent the following parameters to one users table to create multiple records at the same time.

 Parameters: {"users"=>[{"name"}=>{"satoshi"}, {"name"}=>{"yuta"}]}

The following stopparas are received


def users_params

Error that occurred

If you use the permit method after require, I was told "** permit? I don't know such a method **".


[1] pry(#<UsersController>)> params.require(:users).permit
NoMethodError: undefined method `permit'
for #<Array:0x00007f2024a3ee40>from (pry):62:in `users_params'

(The result of binding.pry is output)


Since params.require (: publisheds) is a ** Array class, the permit method cannot be used. ** **


[2] pry(#<UsersController>)> params.require(:users).class
=> Array
[3] pry(#<UsersController>)> params.require(:users).respond_to?("permit")
=> false

Information: permit passes when the array number is specified


[4] pry(#<UsersController>)> params.require(:users)[0].respond_to?("permit")
=> true

[5] pry(#<UsersController>)> params.require(:users)[0].permit(:name)
=> <ActionController::Parameters {"name"=>"satoshi"} permitted: true>

If you come in an array, you should take them out one by one, right? I tought.


Turn with map, disassemble the array, permit and return


def users_params
  params.require(:users).map do |user|

Why map was available

The specification of = ruby ​​that evaluates a block and has an array as a return value implicitly returns (returns) the last evaluated value.

Why can't each be used?

I turn the array and take an argument, but even if I permit in it, it doesn't return a value? Is the permit method a little different because it is a permit rather than a value change (assignment)?

It's difficult to make small differences. .. .. If you have a ruby ​​master, I would like to ask you a question.

Reference: Link of Rurima

specifications of each https://docs.ruby-lang.org/ja/latest/method/Array/i/each.html

map specifications https://docs.ruby-lang.org/ja/latest/class/Array.html#I_COLLECT

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