Fix incorrect JSON Patch output for root path

Author: espadrine

README.md

@@ -9,7 +9,7 @@ gem install json-diff  # Or `gem 'json-diff'` in your Gemfile.
 ```ruby
 require 'json-diff'
 JsonDiff.diff(1, 2)
-#> [{:op => :replace, :path => "/", :value => 2}]
+#> [{:op => :replace, :path => "", :value => 2}]
 ```
 
 Outputs [RFC6902][]. Look at [hana][] for a JSON patch algorithm that can use this output.

lib/json-diff/diff.rb

@@ -1,7 +1,7 @@
 module JsonDiff
 
   def self.diff(before, after, opts = {})
-    path = opts[:path] || '/'
+    path = opts[:path] || ''
     include_addition = (opts[:additions] == nil) ? true : opts[:additions]
     include_moves = (opts[:moves] == nil) ? true : opts[:moves]
     include_was = (opts[:include_was] == nil) ? false : opts[:include_was]

lib/json-diff/operation.rb

@@ -3,6 +3,8 @@ module JsonDiff
   # Convert a list of strings or numbers to an RFC6901 JSON pointer.
   # http://tools.ietf.org/html/rfc6901
   def self.json_pointer(path)
+    return "" if path == []
+
     escaped_path = path.map do |key|
       if key.is_a?(String)
         key.gsub('~', '~0')
@@ -17,7 +19,7 @@ def self.json_pointer(path)
 
   # Add a key to a JSON pointer.
   def self.extend_json_pointer(pointer, key)
-    if pointer == '/'
+    if pointer == ''
       json_pointer([key])
     else
       pointer + json_pointer([key])

lib/json-diff/version.rb

@@ -1,3 +1,3 @@
 module JsonDiff
-  VERSION = '0.3.0'
+  VERSION = '0.3.1'
 end

spec/json-diff/diff_spec.rb

@@ -84,6 +84,15 @@
     ])
   end
 
+  # Trans-type
+
+  it "should be able to diff two objects of mixed type" do
+    diff = JsonDiff.diff(0, "0", include_was: true)
+    expect(diff).to eql([
+      {'op' => 'replace', 'path' => '', 'was' => 0, 'value' => "0"}
+    ])
+  end
+
   # Options
 
   it "should be able to diff two integer arrays with original indices" do

spec/json-diff/operation_spec.rb

@@ -3,7 +3,7 @@
 describe JsonDiff do
   it "should convert the root to a JSON pointer" do
     json_pointer = JsonDiff.json_pointer([])
-    expect(json_pointer).to eql("/")
+    expect(json_pointer).to eql("")
   end
 
   it "should convert a path to a JSON pointer" do