Prevents errors that occur when calling a non-existent JavaScript property with a question mark

[ledsun]

Problem

require 'js'
JS.global[:document].undefinded_method?

This code will cause the following error.

RbError: /bundle/gems/js-2.6.2.dev/lib/js.rb:176:in 'JS::Object#call': TypeError: Cannot read properties of undefined (reading 'undefinded_method')

This is because the JavaScript function existence check is missing.

Solution

Checks for the existence of JavaScript functions.

[kateinoigakukun]

On the second thought, I hesitate to introduce additional semantics differences with/without '?' suffix. I think the root problem here might possibly be the unclear error message thrown when calling non-existing methods.

If the error message is something like TypeError: document.undefinded_method is not a function, is your initial problem satisfied?

[ledsun]

I see.
It is strange that it returns false only when call properties with '?'.
It would be better to have the same error when calling a property with/without '?'.

[kateinoigakukun]

I'll have a time to improve error diagnostic messages anyway:)

[ledsun]

Fixed as follows.
When we call a JavaScript property as a method, we get a NoMethodError.

Perhaps it would be better to;

• raise TypeError when the property is called
• raise NoMethodError when the property is undefined

One thing I am wondering about is the behavior when an existing JavaScript property has an undefiend.