Hashie::Extensions::DeepGrep

CHANGELOG.md

@@ -14,6 +14,7 @@ Any violations of this scheme are considered to be bugs.
 
 * [#523](https://github.com/hashie/hashie/pull/523): Added TOC, ensure a keep-a-changelog formatted CHANGELOG - [@dblock](https://github.com/dblock).
 * [#522](https://github.com/hashie/hashie/pull/522): Added eierlegende Wollmilchsau mascot graphic - [@carolineartz](https://github.com/carolineartz).
+* [#528](https://github.com/hashie/hashie/pull/528): Hashie::extensions::grep - [@vmarutha](https://github.com/vmarutha).
 * Your contribution here.
 
 ### Changed

lib/hashie.rb

@@ -26,6 +26,7 @@ module Extensions
     autoload :DeepFetch,          'hashie/extensions/deep_fetch'
     autoload :DeepFind,           'hashie/extensions/deep_find'
     autoload :DeepLocate,         'hashie/extensions/deep_locate'
+    autoload :Grep,               'hashie/extensions/grep'
     autoload :PrettyInspect,      'hashie/extensions/pretty_inspect'
     autoload :KeyConversion,      'hashie/extensions/key_conversion'
     autoload :MethodAccessWithOverride, 'hashie/extensions/method_access'

lib/hashie/extensions/grep.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'hashie/extensions/deep_locate'
+module Hashie
+  module Extensions
+    module Grep
+      # Performs a depth-first search on deeply nested data structures for
+      # a key and returns all occurrences of the key.
+      #
+      #  options = {
+      #    users: [
+      #      { location: {address: '123 Street'} },
+      #      { location: {address: '234 Street'}}
+      #    ]
+      #  }
+      #  options.extend(Hashie::Extensions::Grep)
+      #  options.grep(/Street/) # => [{:address: '123 Street'}, {:address: '234 Street'}]
+      #
+      #  class MyHash < Hash
+      #    include Hashie::Extensions::Grep
+      #  end
+      #
+      #  my_hash = MyHash.new
+      #  my_hash[:users] = [
+      #    {location: {address: '123 Street'}},
+      #    {location: {address: '234 Street'}}
+      #  ]
+      #  my_hash.grep(/Street/) # => [{:address: '123 Street'}, {:address: '234 Street'}]
+      def grep(pattern)
+        matches = _grep(pattern)
+        matches.empty? ? nil : matches
+      end
+
+      private
+
+      def _match_text?(pattern, text)
+        return false unless text.instance_of?(String) || text.instance_of?(Symbol)
+
+        !pattern.match(text).nil?
+      end
+
+      def _grep(pattern, object = self, matches = [])
+        grep_result = DeepLocate.deep_locate(lambda do |key, value, _object|
+          _match_text?(pattern, key) || _match_text?(pattern, value)
+        end, object)
+
+        matches.concat(grep_result)
+      end
+    end
+  end
+end

spec/hashie/extensions/grep_spec.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Hashie::Extensions::Grep do
+  subject { Class.new(Hash) { include Hashie::Extensions::Grep } }
+  let(:hash) do
+    {
+      library: {
+        books: [
+          { title: 'Call of the Wild' },
+          { title: 'Moby Dick' }
+        ],
+        authors: ['Herman Melville', 'Jack London'],
+        shelves: nil,
+        location: {
+          address: '123 Library St.',
+          title: 'Main Library'
+        }
+      }
+    }
+  end
+  let(:instance) { subject.new.update(hash) }
+
+  describe '#grep' do
+    it 'greps a key from a nested hash' do
+      expect(instance.grep(/^t/)).to eq([
+                                          { title: 'Call of the Wild' },
+                                          { title: 'Moby Dick' },
+                                          { address: '123 Library St.', title: 'Main Library' }
+                                        ])
+    end
+
+    it 'greps a value from a nested hash' do
+      expect(instance.grep(/^M/)).to eq([
+                                          { title: 'Moby Dick' },
+                                          { address: '123 Library St.', title: 'Main Library' }
+                                        ])
+    end
+
+    it 'greps from an array' do
+      expect(instance.grep(/Jack/)).to eq([['Herman Melville', 'Jack London']])
+    end
+
+    it 'returns nil if it does not find a match' do
+      expect(instance.grep(/wahoo/)).to be_nil
+    end
+  end
+end