Class: BetterTranslate::Utils::HashFlattener

Inherits:
Object
  • Object
show all
Defined in:
lib/better_translate/utils/hash_flattener.rb

Overview

Utilities for flattening and unflattening nested hashes

Used to convert nested YAML structures to flat key-value pairs and back again.

Examples:

Flatten nested hash

nested = { "user" => { "name" => "John", "age" => 30 } }
flat = HashFlattener.flatten(nested)
#=> { "user.name" => "John", "user.age" => 30 }

Unflatten to nested hash

flat = { "user.name" => "John", "user.age" => 30 }
HashFlattener.unflatten(flat)
#=> { "user" => { "name" => "John", "age" => 30 } }

Class Method Summary collapse

Class Method Details

.flatten(hash, parent_key = "", separator = ".") ⇒ Hash

Flatten a nested hash to dot-notation keys

Recursively converts nested hashes into a single-level hash with keys joined by a separator (default: ".").

Examples:

Basic flattening

nested = {
  "config" => {
    "database" => {
      "host" => "localhost"
    }
  }
}
HashFlattener.flatten(nested)
#=> { "config.database.host" => "localhost" }

Custom separator

HashFlattener.flatten(nested, "", "/")
#=> { "config/database/host" => "localhost" }

Parameters:

  • hash (Hash) —

    Nested hash to flatten

  • parent_key (String) (defaults to: "") —

    Parent key prefix (used internally for recursion)

  • separator (String) (defaults to: ".") —

    Key separator (default: ".")

Returns:

  • (Hash) —

    Flattened hash



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# File 'lib/better_translate/utils/hash_flattener.rb', line 49

def self.flatten(hash, parent_key = "", separator = ".")
  initial_hash = {} # : Hash[String, untyped]
  hash.each_with_object(initial_hash) do |(key, value), result|
    new_key = parent_key.empty? ? key.to_s : "#{parent_key}#{separator}#{key}"

    if value.is_a?(Hash)
      result.merge!(flatten(value, new_key, separator))
    else
      result[new_key] = value
    end
  end
end

.unflatten(hash, separator = ".") ⇒ Hash

Unflatten a hash with dot-notation keys to nested structure

Converts a flat hash with delimited keys back into a nested hash structure.

Examples:

Basic unflattening

flat = { "config.database.host" => "localhost" }
HashFlattener.unflatten(flat)
#=> {
#     "config" => {
#       "database" => {
#         "host" => "localhost"
#       }
#     }
#   }

Custom separator

flat = { "config/database/host" => "localhost" }
HashFlattener.unflatten(flat, "/")
#=> { "config" => { "database" => { "host" => "localhost" } } }

Parameters:

  • hash (Hash) —

    Flattened hash

  • separator (String) (defaults to: ".") —

    Key separator (default: ".")

Returns:

  • (Hash) —

    Nested hash



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# File 'lib/better_translate/utils/hash_flattener.rb', line 87

def self.unflatten(hash, separator = ".")
  initial_hash = {} # : Hash[String, untyped]
  hash.each_with_object(initial_hash) do |(key, value), result|
    keys = key.split(separator)
    last_key = keys.pop

    # Build nested structure
    nested = keys.reduce(result) do |memo, k|
      memo[k] ||= {}
      memo[k]
    end

    nested[last_key] = value if last_key
  end
end