Class: Morphix::Transformer

Inherits:
Object
  • Object
show all
Defined in:
lib/morphix/transformer.rb

Overview

The Transformer class provides a DSL for transforming data structures like hashes and JSON. It allows you to define transformation rules that can be applied to input data, making it perfect for API response normalization, JSON reshaping, and ETL pipelines.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Transformer

Creates a new transformer with the given block

Parameters:

  • block (Proc) —

    The block defining the transformations



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# File 'lib/morphix/transformer.rb', line 10

def initialize(&)
  @transformations = []
  instance_eval(&) if block_given?
end

Instance Method Details

#apply(input) ⇒ Hash

Applies the transformations to the input hash

Parameters:

  • input (Hash) —

    The input hash to transform

Returns:

  • (Hash) —

    The transformed hash



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# File 'lib/morphix/transformer.rb', line 63

def apply(input)
  result = input.dup
  @transformations.each { |transformation| apply_transformation(result, transformation) }
  result
end

#map(key, &block) ⇒ self

Transforms a value while preserving its key

Parameters:

  • key (Symbol) —

    The key whose value to transform

  • block (Proc) —

    The block to transform the value

Returns:

  • (self) —

    Returns self for method chaining



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# File 'lib/morphix/transformer.rb', line 29

def map(key, &block)
  @transformations << { type: :map, key:, block: }
  self
end

#map_collection(key, &block) ⇒ self

Transforms an array of hashes

Parameters:

  • key (Symbol) —

    The key containing the array

  • block (Proc) —

    The block defining the transformations for each hash

Returns:

  • (self) —

    Returns self for method chaining



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# File 'lib/morphix/transformer.rb', line 55

def map_collection(key, &block)
  @transformations << { type: :map_collection, key:, block: }
  self
end

#reject(key) ⇒ self

Removes a key from the hash

Parameters:

  • key (Symbol) —

    The key to remove

Returns:

  • (self) —

    Returns self for method chaining



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# File 'lib/morphix/transformer.rb', line 37

def reject(key)
  @transformations << { type: :reject, key: }
  self
end

#rename(old_key, to:, &block) ⇒ self

Renames a key to a new name, optionally transforming its value

Parameters:

  • old_key (Symbol) —

    The key to rename

  • to (Symbol) —

    The new key name

  • block (Proc, nil) —

    Optional block to transform the value

Returns:

  • (self) —

    Returns self for method chaining



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# File 'lib/morphix/transformer.rb', line 20

def rename(old_key, to:, &block)
  @transformations << { type: :rename, old_key:, new_key: to, block: }
  self
end

#reshape(key, &block) ⇒ self

Transforms a nested hash structure

Parameters:

  • key (Symbol) —

    The key containing the nested hash

  • block (Proc) —

    The block defining the nested transformations

Returns:

  • (self) —

    Returns self for method chaining



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# File 'lib/morphix/transformer.rb', line 46

def reshape(key, &block)
  @transformations << { type: :reshape, key:, block: }
  self
end