In my effort to learn more about Rails and all of it’s magic, I dove into the docs and wrote up a concise version from Ruby Guides. This is a concise version from Ruby Guides. For more methods and in depth documentation, visit https://guides.rubyonrails.org/active_support_core_extensions.html
#blank?, #present?
blank values include nil, false, strings of whitespace, empty arrays/hashes
#presence
returns receiver or nil
| name = user[:name].presence | ‘No name’ |
#deep_dup
Dup is a Ruby method, but does not dup an object containing other objects.
#try
# without try
unless @number.nil?
@number.next
end
# with try
@number.try(:next)
#to_param
create a custom param for an object
class Article
def to_param
"#{id}=#{name.paramterize}"
end
endarticle_path(@article)
=> "/articles/1-dog-show"
#to_query(namespace = nil)
constructs a query string from a hash. If given a namespace, it will be used to enclose key names and use any to_param.
{ name: 'bob', age: '25' }.to_query
=> "name=Bob&age=25"
#with_options
A way to group options, often used with ActiveRecord models.
#instance_values
returns a hash that maps instance values without the ‘@’
class User
def initialize(name, age)
@name, @age = name, age
end
end
User.new("Andrea", 25).instance_values
=> {"name" => "Andrea", "age" => 25}
#instance_variable_names
returns an array of instance variables
class User
def initialize(name, age)
@name, @age = name, age
end
end
User.new("Andrea", 25).instance_variable_names
=> [ "@name", "@age" ]
#in
returns whether an object is in another object, returns a boolean or an error if the argument does not respond to include?
5.in?([1,2,3,4,5]) # => true
"mo".in?("tomorrow") # => true
25.in?(50..100) # => false
1.in?(1) # => ArgumentError
delegate, delegate_missing_to
forwards methods. If there is an association between 2 objects, this way they can forward methods instead of object.method_name
class Article < ApplicationRecord
has_one :author delegate :author_name, to: author
delegate_missing_to :author
end
#html_safe
Marks strings as being safe to insert into HTML
"".html_safe? => false
s = "".html_safe
s.html_safe? # => true
#squish
Strips leading and trailing whitespace, and substitutes with a space.
" \n disco\n\r \t ball \n".squish # => "disco ball"
#truncate, #truncate_words
returns a copy of its receiver based on given length
"A long time ago, in a galaxy far, far, away".truncate(18)
=> "A long time ago...""A long time ago, in a galaxy far, far, away".truncate_words(4)
=> "A long time ago..."
#starts_with?, #ends_with?
"hello".starts_with?("h") => true
"hello".ends_with?("h") => false
#pluralize(count = 0), #singularize
"animal".pluralize => "animals"
"animals".singularize => "animal
#camelize, #underscore
"full_name".camelize => "FullName"
"full_name".camelize(:lower) => "fullName""fullName".underscore => "full_name"
"User::Session".underscore => "user/session"
#humanize
"name".humanize => "Name"
"author_id".humanize => "Author"
"author_id".humanize(capitalize: false) => "author"
"comments_count".humanize => "Comments count"
"_id".humanize => "Id"
#symbolize_keys
{ nil => nil, 5 => 5, "name" => "Bob }.symbolize_keys
=> { nil => nil, 5 => 5, :name => "Bob }.
For more methods, visit https://guides.rubyonrails.org/active_support_core_extensions.html