HashDiff

HashDiff is a ruby library to compute the smallest difference between two hashes.

Requirements

HashDiff is tested on following platforms:

• 1.8.7
• 1.9.2
• 1.9.3
• rbx
• rbx-2.0
• ree
• jruby
• ruby-head

Usage

If you're using bundler, add following:

gem 'hashdiff'

Or, you can run gem install hashdiff, then add following line to your ruby file which uses HashDiff:

require 'hashdiff'

Quick Start

You can find full docs here: Documentation

Diff

Two simple hash:

a = {a:3, b:2}
b = {}

diff = HashDiff.diff(a, b)
diff.should == [['-', 'a', 3], ['-', 'b', 2]]

More complex hash:

a = {a:{x:2, y:3, z:4}, b:{x:3, z:45}}
b = {a:{y:3}, b:{y:3, z:30}}

diff = HashDiff.diff(a, b)
diff.should == [['-', 'a.x', 2], ['-', 'a.z', 4], ['-', 'b.x', 3], ['~', 'b.z', 45, 30], ['+', 'b.y', 3]]

Array in hash:

a = {a:[{x:2, y:3, z:4}, {x:11, y:22, z:33}], b:{x:3, z:45}}
b = {a:[{y:3}, {x:11, z:33}], b:{y:22}}

diff = HashDiff.best_diff(a, b)
diff.should == [['-', 'a[0].x', 2], ['-', 'a[0].z', 4], ['-', 'a[1].y', 22], ['-', 'b.x', 3], ['-', 'b.z', 45], ['+', 'b.y', 22]]

Patch

patch example:

a = {a: 3}
b = {a: {a1: 1, a2: 2}}

diff = HashDiff.diff(a, b)
HashDiff.patch(a, diff).should == b

unpatch example:

a = [{a: 1, b: 2, c: 3, d: 4, e: 5}, {x: 5, y: 6, z: 3}, 1]
b = [1, {a: 1, b: 2, c: 3, e: 5}]

diff = HashDiff.diff(a, b) # diff two array is OK
HashDiff.unpatch(b, diff).should == a

License

HashDiff is distributed under the MIT-LICENSE.