Negative numbers (#126)

* update float/integer regex to handle negative values

* bump version to 3.6.1

* spec

* update hash syntax in specs

* change to major version 3.7.0

* use eq

* actual bump to major version v4

* update gem version in readme

* v3->v4 migration guide

* add sample custom parser

* Add comment syntax highlighting

Co-authored-by: Conor Hawes <[email protected]>

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    decanter (3.6.0)
+    decanter (4.0.0)
       actionpack (>= 4.2.10)
       activesupport
       rails-html-sanitizer (>= 1.0.4)

README.md

@@ -3,7 +3,7 @@
 Decanter is a Ruby gem that makes it easy to transform incoming data before it hits the model. You can think of Decanter as the opposite of Active Model Serializers (AMS). While AMS transforms your outbound data into a format that your frontend consumes, Decanter transforms your incoming data into a format that your backend consumes.
 
 ```ruby
-gem 'decanter', '~> 3.0'
+gem 'decanter', '~> 4.0'
 ```
 
 ## Migration Guides

lib/decanter/parser/float_parser.rb

@@ -1,7 +1,7 @@
 module Decanter
   module Parser
     class FloatParser < ValueParser
-      REGEX = /(\d|[.])/
+      REGEX = /(\d|[.]|[-])/
 
       allow Float, Integer
 

lib/decanter/parser/integer_parser.rb

@@ -1,7 +1,7 @@
 module Decanter
   module Parser
     class IntegerParser < ValueParser
-      REGEX = /(\d|[.])/
+      REGEX = /(\d|[.]|[-])/
 
       allow Integer
 

lib/decanter/version.rb

@@ -1,3 +1,3 @@
 module Decanter
-  VERSION = '3.6.0'.freeze
+  VERSION = '4.0.0'.freeze
 end

migration-guides/v4.0.0.md

@@ -0,0 +1,35 @@
+# v4.0.0 Migration Guide
+
+_Note: this guide assumes you are upgrading from decanter v3 to v4._
+
+This version contains the following breaking changes:
+
+1. `FloatParser` and `IntegerParser` have been updated to address a bug where negative numbers were being parsed as positive. In the (unlikely) event that your project was relying on the previous behavior, you can pin the gem version to `v3.6.0` or include the legacy version(s) of the parsers as custom parsers in your project.
+
+To add a custom parser, add the new parser class to your project:
+
+```rb
+# app/parsers/postive_float_parser.rb
+
+class PositiveFloatParser < Decanter::Parser::ValueParser
+  REGEX = /(\d|[.])/
+
+  allow Float, Integer
+
+  parser do |val, options|
+    raise Decanter::ParseError.new 'Expects a single value' if val.is_a? Array
+    next if (val.nil? || val === '')
+    val.scan(REGEX).join.try(:to_f)
+  end
+end
+```
+
+Then, use the appropriate key to look up the parser in your decanter:
+
+```rb
+# app/decanters/product_decanter.rb
+
+class ProductDecanter <  Decanter::Base
+  input :price, :positive_float #=> PositiveFloatParser
+end
+```

spec/decanter/parser/float_parser_spec.rb

@@ -8,20 +8,28 @@
 
   describe '#parse' do
     context 'with a string' do
-      it 'returns a float' do
-        expect(parser.parse(name, '1.00')).to match({name => 1.00})
+      context 'with a positive value' do
+        it 'returns a positive float' do
+          expect(parser.parse(name, '1.00')).to eq({ foo: 1.00 })
+        end
+      end
+
+      context 'with a negative value' do
+        it 'returns a negative float' do
+          expect(parser.parse(name, '-1.00')).to eq({ foo: -1.00 })
+        end
       end
     end
 
     context 'with empty string' do
       it 'returns nil' do
-        expect(parser.parse(name, '')).to match({name => nil})
+        expect(parser.parse(name, '')).to eq({ foo: nil })
       end
     end
 
     context 'with nil' do
       it 'returns nil' do
-        expect(parser.parse(name, nil)).to match({name => nil})
+        expect(parser.parse(name, nil)).to eq({ foo: nil })
       end
     end
 

spec/decanter/parser/integer_parser_spec.rb

@@ -8,20 +8,28 @@
 
   describe '#parse' do
     context 'with a string' do
-      it 'returns an integer' do
-        expect(parser.parse(name, '1')).to match({name => 1})
+      context 'with a positive value' do
+        it 'returns a positive integer' do
+          expect(parser.parse(name, '1')).to eq({ foo: 1 })
+        end
+      end
+
+      context 'with a negative value' do
+        it 'returns a negative integer' do
+          expect(parser.parse(name, '-1')).to eq({ foo: -1 })
+        end
       end
     end
 
     context 'with empty string' do
       it 'returns nil' do
-        expect(parser.parse(name, '')).to match({name => nil})
+        expect(parser.parse(name, '')).to eq({ foo: nil })
       end
     end
 
     context 'with nil' do
       it 'returns nil' do
-        expect(parser.parse(name, nil)).to match({name => nil})
+        expect(parser.parse(name, nil)).to eq({ foo: nil })
       end
     end