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is_a? and kind_of? will return true for instances from derived classes. Quick aside: if you use this in conditional logic you need to use parentheses; eg, if foo. is_a?(String) && ...
Use the typeof operator to check if a variable is a string, e.g. if (typeof variable === 'string') . If the typeof operator returns "string" , then the variable is a string. In all other cases the variable isn't a string. Copied!
The proper way to determine the "type" of an object, which is a wobbly term in the Ruby world, is to call object. class . Since classes can inherit from other classes, if you want to determine if an object is "of a particular type" you might call object.
I think you are looking for instance_of?. is_a? and kind_of? will return true for instances from derived classes.
class X < String
end
foo = X.new
foo.is_a? String # true
foo.kind_of? String # true
foo.instance_of? String # false
foo.instance_of? X # true
A more duck-typing approach would be to say
foo.respond_to?(:to_str)
to_str indicates that an object's class may not be an actual descendant of the String, but the object itself is very much string-like (stringy?).
You can do:
foo.instance_of?(String)
And the more general:
foo.kind_of?(String)
foo.instance_of? String
or
foo.kind_of? String
if you you only care if it is derrived from String somewhere up its inheritance chain
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