`SObject.describe_field` method

[rferg]

SObject.describe is a nice convenience method when I want to investigate the SF metadata behind an object.

However, I'm often only looking for a particular field and the object that's returned from this endpoint is rather large and unruly. For example, to get the metadata for a particular field, I run something like this:

MyObject.describe.fields.find { |f| f['name'] == 'My_Field__c' }

Which is kind of verbose and requires having to look up the name of the SF field that maps to the object attribute.

It would be nice if ActiveForce exposed a method that did this for me, including mapping a symbol for the attribute name to the correct SF field name. Something like:

MyObject.describe_field(:my_field)

It should also take a string for the actual SF field as well, which should be pretty easy to implement.

MyObject.describe_field('My_Field__c')

Or, possibly it should be variadic and take one or many field names, returning an array of field metadata:

MyObject.describe_fields(:my_field, :another_field, 'One_More__c')

[rferg]

I'm happy to write up a PR for this--should be straightforward. But wanted to open for discussion before moving forward. Would anyone else actually use this or is this just a very niche nice-to-have? What should the API be if it is actually useful?