HashDeepDiff

Find the exact difference between two Hash objects and build a report to visualize it. Works for other objects too but why would you do that :/

Alternative solutions hashdiff by liufengyun and hash_diff by CodingZeal

Installation

Add this line to your application's Gemfile:

gem 'hash_deep_diff'

And then execute:

$ bundle

Or install it yourself as:

$ gem install hash_deep_diff

Usage

Basic

left = { a: :a }
right = { a: :b }

print HashDeepDiff::Comparison.new(left, right).report

- left[a] = a
+ left[a] = b

Arrays

left = [1, 2, { a: :a }]
right = [2, { a: :b }, 3]

print HashDeepDiff::Comparison.new(left, right).report

-left[...] = [1]
+left[...] = [3]
-left[{}][a] = a
+left[{}][a] = b

Nesting

left  = { a: [1, 2, { a: :a } ], b: { c: [1, 2, { d: :e } ] } }
right = { a: [2, { a: :b }, 3], b: { c: { f: { g: :h } } } }

print HashDeepDiff::Comparison.new(left, right).report

-left[a][...] = [1]
+left[a][...] = [3]
-left[a][{}][a] = a
+left[a][{}][a] = b
+left[b][c][...][f] = {}
+left[b][c][...][f][g] = h
-left[b][c][...][f] = [1, 2]
-left[b][c][{}][d] = e

Reporting Engines

You can choose from the default diff-like reporting engine (examples are above) and YML reporting engine

left  = { a: [1, 2, { a: :a } ], b: { c: [1, 2, { d: :e } ] } }
right = { a: [2, { a: :b }, 3], b: { c: { f: { g: :h } } } }

Raw Report

print HashDeepDiff::Comparison.new(left, right, reporting_engine: HashDeepDiff::Reports::Yml).raw_report
=> {"additions"=>{:a=>[3, {:a=>:b}], :b=>{:c=>[{:f=>{:g=>:h}}]}},
    "deletions"=>{:a=>[1, {:a=>:a}], :b=>{:c=>[1, 2, {:d=>:e}]}}}

YML Report

print HashDeepDiff::Comparison.new(left, right, reporting_engine: HashDeepDiff::Reports::Yml).report

---
additions:
  :a:
  - 3
  - :a: :b
  :b:
    :c:
    - :f:
        :g: :h
deletions:
  :a:
  - 1
  - :a: :a
  :b:
    :c:
    - 1
    - 2
    - :d: :e

please see Documentation for more information or Reporting test

Customization

You can implement and use your own reporting engines with the default HashDeepDiff::Delta objects as a source of the report. In order to do so implement your own version of the reporting engine (example can be found here) and inject it into a Comparison

left = { a: :a }
right = { a: :b }

HashDeepDiff::Comparison.new(left, right, reporting_engine: CustomEngine).report

Contributing

Bug reports and pull requests are welcome on GitHub at bpohoriletz.