Class: Object
- Inherits:
- BasicObject
- Includes:
- Kernel
- Defined in:
- lib/buff/extensions/object/try.rb,
lib/buff/extensions/kernel.rb,
lib/buff/extensions/object/blank.rb
Overview
Borrowed and modified from https://github.com/rails/rails/blob/master/activesupport/lib/active_support/core_ext/object/blank.rb
Instance Method Summary collapse
-
#blank? ⇒ Boolean
An object is blank if it’s false, empty, or a whitespace string.
-
#presence ⇒ Object
Returns object if it’s
present?
otherwise returnsnil
. -
#present? ⇒ Boolean
An object is present if it’s not
blank?
. -
#try(*a, &b) ⇒ Object
Invokes the public method whose name goes as first argument just like
public_send
does, except that if the receiver does not respond to it the call returnsnil
rather than raising an exception. -
#try!(*a, &b) ⇒ Object
Same as #try, but will raise a NoMethodError exception if the receiving is not nil and does not implemented the tried method.
Methods included from Buff::Extensions::Kernel::Reporting
#capture, #enable_warnings, #quietly, #silence_stderr, #silence_stream, #silence_warnings, #suppress, #with_warnings
Instance Method Details
#blank? ⇒ Boolean
An object is blank if it’s false, empty, or a whitespace string. For example, ”, ‘ ’, nil
, [], and {} are all blank.
This simplifies:
if address.nil? || address.empty?
…to:
if address.blank?
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# File 'lib/buff/extensions/object/blank.rb', line 15 def blank? respond_to?(:empty?) ? empty? : !self end |
#presence ⇒ Object
Returns object if it’s present?
otherwise returns nil
. object.presence
is equivalent to object.present? ? object : nil
.
This is handy for any representation of objects where blank is the same as not present at all. For example, this simplifies a common check for HTTP POST/query parameters:
state = params[:state] if params[:state].present?
country = params[:country] if params[:country].present?
region = state || country || 'US'
…becomes:
region = params[:state].presence || params[:country].presence || 'US'
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# File 'lib/buff/extensions/object/blank.rb', line 38 def presence self if present? end |
#present? ⇒ Boolean
An object is present if it’s not blank?
.
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# File 'lib/buff/extensions/object/blank.rb', line 20 def present? !blank? end |
#try(*a, &b) ⇒ Object
Invokes the public method whose name goes as first argument just like public_send
does, except that if the receiver does not respond to it the call returns nil
rather than raising an exception.
This method is defined to be able to write
@person.try(:name)
instead of
@person ? @person.name : nil
try
returns nil
when called on nil
regardless of whether it responds to the method:
nil.try(:to_i) # => nil, rather than 0
Arguments and blocks are forwarded to the method if invoked:
@posts.try(:each_slice, 2) do |a, b|
...
end
The number of arguments in the signature must match. If the object responds to the method the call is attempted and ArgumentError
is still raised otherwise.
If try
is called without arguments it yields the receiver to a given block unless it is nil
:
@person.try do |p|
...
end
Please also note that try
is defined on Object
, therefore it won’t work with instances of classes that do not have Object
among their ancestors, like direct subclasses of BasicObject
. For example, using try
with SimpleDelegator
will delegate try
to the target instead of calling it on delegator itself.
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# File 'lib/buff/extensions/object/try.rb', line 44 def try(*a, &b) if a.empty? && block_given? yield self else public_send(*a, &b) if respond_to?(a.first) end end |
#try!(*a, &b) ⇒ Object
Same as #try, but will raise a NoMethodError exception if the receiving is not nil and does not implemented the tried method.
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# File 'lib/buff/extensions/object/try.rb', line 54 def try!(*a, &b) if a.empty? && block_given? yield self else public_send(*a, &b) end end |