dry-types 0.15

Hash Schemas (deprecated API)

[DEPRECATED] The following API is already removed in 0.15, use new configurable hash schemas as a replacement.

The built-in Hash type has constructors that you can use to define hashes with explicit schemas and coercible values using the built-in types. The different constructor types support different use cases that involve unexpected keys, missing keys, default values, and key coercion.

Hash schemas are typically used under the hood of other libraries. In example dry-validation uses :symbolized schema in Form validations, which safely processes values in a hash and returns output with symbolized keys or dry-struct uses hash schemas to process struct attributes. If you want to use hash schemas standalone, or configure them for your dry structs, it's important to understand differences in behavior:

Input contains a value with an invalid type

Input omits a key for a value that does not have a default

Input omits a key for a value that has a default

Input includes a key that was not specified in the schema

Input contains nil for a value that specifies a default

Input contains string keys instead of symbol keys

Example Usage

Hash Schema

# using simple kernel coercions
hash = Types::Hash.schema(name: Types::String, age: Types::Coercible::Integer)

hash[name: 'Jane', age: '21']
# => { :name => "Jane", :age => 21 }

# using form param coercions
hash = Types::Hash.schema(name: Types::String, birthdate: Form::Date)

hash[name: 'Jane', birthdate: '1994-11-11']
# => { :name => "Jane", :birthdate => #<Date: 1994-11-11 ((2449668j,0s,0n),+0s,2299161j)> }

Permissive Schema

Permissive hash will raise errors when keys are missing or value types are incorrect.

hash = Types::Hash.permissive(name: Types::String, age: Types::Coercible::Integer)

hash[email: 'jane@doe.org', name: 'Jane', age: 21]
# => Dry::Types::SchemaKeyError: :email is missing in Hash input

Symbolized Schema

Symbolized hash will turn string key names into symbols

hash = Types::Hash.symbolized(name: Types::String, age: Types::Coercible::Integer)

hash['name' => 'Jane', 'age' => '21']
# => { :name => "Jane", :age => 21 }

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