# Puppet Function: ensure_prefix

Defined in:
  lib/puppet/parser/functions/ensure_prefix.rb

Function type:
  Ruby 3.x API

## Overview

ensure_prefix() ⇒ `Any`

This function ensures a prefix for all elements in an array or the keys in a hash.

Examples:

ensure_prefix(=> 1, 'b' => 2, 'p.c' => 3, 'p.')

Will return: { 'p.a' => 1, 'p.b' => 2, 'p.c' => 3, }

ensure_prefix(['a', 'p.b', 'c'], 'p.')

Will return: ['p.a', 'p.b', 'p.c']

Returns:

- (`Any`)

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    # File 'lib/puppet/parser/functions/ensure_prefix.rb', line 3

    newfunction(:ensure_prefix, type: :rvalue, doc: <<-EOS
      This function ensures a prefix for all elements in an array or the keys in a hash.

      *Examples:*

        ensure_prefix({'a' => 1, 'b' => 2, 'p.c' => 3}, 'p.')

      Will return:
        {
          'p.a' => 1,
          'p.b' => 2,
          'p.c' => 3,
        }

        ensure_prefix(['a', 'p.b', 'c'], 'p.')

      Will return:
        ['p.a', 'p.b', 'p.c']
    EOS
               ) do |arguments|
      if arguments.size < 2
        raise(Puppet::ParseError, 'ensure_prefix(): Wrong number of arguments ' \
          "given (#{arguments.size} for 2)")
      end

      enumerable = arguments[0]

      unless enumerable.is_a?(Array) || enumerable.is_a?(Hash)
        raise Puppet::ParseError, "ensure_prefix(): expected first argument to be an Array or a Hash, got #{enumerable.inspect}"
      end

      prefix = arguments[1] if arguments[1]

      if prefix
        unless prefix.is_a?(String)
          raise Puppet::ParseError, "ensure_prefix(): expected second argument to be a String, got #{prefix.inspect}"
        end
      end

      result = if enumerable.is_a?(Array)
                 # Turn everything into string same as join would do ...
                 enumerable.map do |i|
                   i = i.to_s
                   prefix && !i.start_with?(prefix) ? prefix + i : i
                 end
               else
                 Hash[enumerable.map do |k, v|
                   k = k.to_s
                   [prefix && !k.start_with?(prefix) ? prefix + k : k, v]
                 end]
               end

      return result
    end