Backport stdlib::to_json_pretty from upstream

Author: vulpine

lib/puppet/functions/stdlib/to_json_pretty.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require 'json'
+
+# @summary
+#   Convert data structure and output to pretty JSON
+#
+# @example **Usage**
+#   * how to output pretty JSON to file
+#     file { '/tmp/my.json':
+#       ensure  => file,
+#       content => stdlib::to_json_pretty($myhash),
+#     }
+#
+#   * how to output pretty JSON skipping over keys with undef values
+#     file { '/tmp/my.json':
+#       ensure  => file,
+#       content => stdlib::to_json_pretty({
+#         param_one => 'value',
+#         param_two => undef,
+#       }, true),
+#     }
+#
+#   * how to output pretty JSON using tabs for indentation
+#     file { '/tmp/my.json':
+#       ensure  => file,
+#       content => stdlib::to_json_pretty({
+#         param_one => 'value',
+#         param_two => {
+#           param_more => 42,
+#         },
+#       }, nil, {indent => '    '}),
+#     }
+
+Puppet::Functions.create_function(:'stdlib::to_json_pretty') do
+  # @param data
+  #   data structure which needs to be converted to pretty json
+  # @param skip_undef
+  #   value `true` or `false`
+  # @param opts
+  #   hash-map of settings passed to JSON.pretty_generate, see
+  #   https://ruby-doc.org/stdlib-2.0.0/libdoc/json/rdoc/JSON.html#method-i-generate.
+  #   Note that `max_nesting` doesn't take the value `false`; use `-1` instead.
+  # @return
+  #   converted data to pretty json
+  dispatch :to_json_pretty do
+    param 'Variant[Hash, Array]', :data
+    optional_param 'Optional[Boolean]', :skip_undef
+    optional_param 'Struct[{
+indent       => Optional[String],
+space        => Optional[String],
+space_before => Optional[String],
+object_nl    => Optional[String],
+array_nl     => Optional[String],
+allow_nan    => Optional[Boolean],
+max_nesting  => Optional[Integer[-1,default]],
+}]', :opts
+  end
+
+  def to_json_pretty(data, skip_undef = false, opts = nil)
+    # It's not possible to make an abstract type that can be either a boolean
+    # false or an integer, so we use -1 as the falsey value
+    if opts
+      opts = opts.transform_keys(&:to_sym)
+
+      opts[:max_nesting] = false if opts[:max_nesting] == -1
+    end
+
+    data = data.compact if skip_undef && (data.is_a?(Array) || Hash)
+    # Call ::JSON to ensure it references the JSON library from Ruby's standard library
+    # instead of a random JSON namespace that might be in scope due to user code.
+    JSON.pretty_generate(data, opts) << "\n"
+  end
+end