class Object

Public Instance Methods

blank?() click to toggle source

An object is blank if it's false, empty, or a whitespace string. For example, nil, '', ' ', [], {}, and false are all blank.

This simplifies

!address || address.empty?

to

address.blank?

@return [true, false]

# File lib/simple_ext/object/blank.rb, line 17
def blank?
  respond_to?(:empty?) ? !!empty? : !self
end
in?(another_object) click to toggle source

Returns true if this object is included in the argument. Argument must be any object which responds to #include?. Usage:

characters = ["Konata", "Kagami", "Tsukasa"]
"Konata".in?(characters) # => true

This will throw an ArgumentError if the argument doesn't respond to #include?.

# File lib/simple_ext/object/inclusion.rb, line 12
def in?(another_object)
  another_object.include?(self)
rescue NoMethodError
  raise ArgumentError.new("The parameter passed to #in? must respond to #include?")
end
instance_values() click to toggle source

Returns a hash with string keys that maps instance variable names without “@” to their corresponding values.

class C
  def initialize(x, y)
    @x, @y = x, y
  end
end

C.new(0, 1).instance_values # => {"x" => 0, "y" => 1}
# File lib/simple_ext/object/instance_variables.rb, line 14
def instance_values
  Hash[instance_variables.map { |name| [name[1..-1], instance_variable_get(name)] }]
end
instance_variable_names() click to toggle source

Returns an array of instance variable names as strings including “@”.

class C
  def initialize(x, y)
    @x, @y = x, y
  end
end

C.new(0, 1).instance_variable_names # => ["@y", "@x"]
# File lib/simple_ext/object/instance_variables.rb, line 27
def instance_variable_names
  instance_variables.map(&:to_s)
end
presence() click to toggle source

Returns the receiver if it's present otherwise returns nil. object.presence is equivalent to

object.present? ? object : nil

For example, something like

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'

@return [Object]

# File lib/simple_ext/object/blank.rb, line 44
def presence
  self if present?
end
presence_in(another_object) click to toggle source

Returns the receiver if it's included in the argument otherwise returns nil. Argument must be any object which responds to #include?. Usage:

params[:bucket_type].presence_in %w( project calendar )

This will throw an ArgumentError if the argument doesn't respond to #include?.

@return [Object]

# File lib/simple_ext/object/inclusion.rb, line 26
def presence_in(another_object)
  in?(another_object) ? self : nil
end
present?() click to toggle source

An object is present if it's not blank.

@return [true, false]

# File lib/simple_ext/object/blank.rb, line 24
def present?
  !blank?
end
to_param() click to toggle source

Alias of to_s.

# File lib/simple_ext/object/to_query.rb, line 7
def to_param
  to_s
end
to_query(key) click to toggle source

Converts an object into a string suitable for use as a URL query string, using the given key as the param name.

# File lib/simple_ext/object/to_query.rb, line 13
def to_query(key)
  "#{CGI.escape(key.to_param)}=#{CGI.escape(to_param.to_s)}"
end
try(*a, &b) click to toggle source

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.name if @person

try calls can be chained:

@person.try(:spouse).try(:name)

instead of

@person.spouse.name if @person && @person.spouse

try will also return nil if the receiver does not respond to the method:

@person.try(:non_existing_method) # => nil

instead of

@person.non_existing_method if @person.respond_to?(:non_existing_method) # => 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 in case of argument mismatch.

If try is called without arguments it yields the receiver to a given block unless it is nil:

@person.try do |p|
  ...
end

You can also call try with a block without accepting an argument, and the block will be instance_eval'ed instead:

@person.try { upcase.truncate(50) }

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.

# File lib/simple_ext/object/try.rb, line 5
  
try!(method_name = nil, *args) { |self| ... } click to toggle source
# File lib/simple_ext/object/try.rb, line 93
def try!(method_name = nil, *args, &b)
  if method_name.nil? && block_given?
    if b.arity == 0
      instance_eval(&b)
    else
      yield self
    end
  else
    public_send(method_name, *args, &b)
  end
end