Contents

---
title: Params and Options
layout: gem-single
name: dry-initializer
---

Use `param` to define plain argument:

```ruby
require 'dry-initializer'

class User
  extend  Dry::Initializer

  param :name
  param :email
end

user = User.new 'Andrew', '[e-mail]'
user.name  # => 'Andrew'
user.email # => '[e-mail]'
```

Use `option` to define named (hash) argument:

```ruby
require 'dry-initializer'

class User
  extend Dry::Initializer

  option :name
  option :email
end

user = User.new email: '[e-mail]', name: 'Andrew'
user.name  # => 'Andrew'
user.email # => '[e-mail]'
```

Options can be renamed using `:as` key:

```ruby
require 'dry-initializer'

class User
  extend Dry::Initializer

  option :name, as: :username
end

user = User.new name: "Joe"
user.username                         # => "Joe"
user.instance_variable_get :@username # => "Joe"
user.instance_variable_get :@name     # => nil
user.respond_to? :name                # => false
```

You can also define several ways of initializing the same argument via different options:

```ruby
require 'dry-initializer'

class User
  extend Dry::Initializer

  option :phone
  option :telephone, as: :phone
  option :name, optional: true
end

User.new(phone: '1234567890').phone     # => '1234567890'
User.new(telephone: '1234567890').phone # => '1234567890'
```

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
dry-initializer-3.0.3	docsite/source/params-and-options.html.md
dry-initializer-3.0.2	docsite/source/params-and-options.html.md