Implement the JS::Object#to_b method.

[ledsun]

A boolean value in JavaScript is always a JS::Object instance from Ruby's point of view.
Therefore, if we use the boolean value returned by a JavaScript function as the condition for an if expression in Ruby, the if expression will always be true.

if searchParams.has('phrase')
  # Always pass through here.
  ...
else
  ...
end

Think of searchParams as an instance of JavaScript's SearchParams class.
This is not the expected behavior.

Therefore, we can implement the JS::Object#to_b method to convert JavaScript boolean values to Ruby boolean values.

It is intended to be used in the following ways:

if searchParams.has('phrase').to_b
  ...
else
  ...
end

I implemented the to_b method by referring to the implementation of the to_s method.
If you prefer a different implementation, please let me know.

[kateinoigakukun]

I am a little reluctant about introducing a new conversion method that is not used in the Ruby standard library.¹
As you know, we already have to_i, to_f, and to_s, so you may feel introducing to_b is a straightforward way. However, we already have JS::Object#== and we can compare a receiver object with JS.eval("return true") to satisfy the given use case. (On the other hand, other to_x has no other way to satisfy their requirement)

Therefore, I'd like to suggest defining JS::True = JS.eval("return true") and JS::False as well instead of adding a new conversion method.

Footnotes

1. Actually to_b has been rejected in Ruby repeatedly https://bugs.ruby-lang.org/issues/6180 https://bugs.ruby-lang.org/issues/11848 ↩

[ledsun]

We did not consider the point of matching the standard Ruby method definitions.
I agree with the policy to define JS::True and JS::False.