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https://github.com/falm/attribute-depends-calculator
Automatically calculate a collection of depends attribute of ActiveRecord
https://github.com/falm/attribute-depends-calculator
activerecord activerecord-callbacks calculator rails
Last synced: about 1 month ago
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Automatically calculate a collection of depends attribute of ActiveRecord
- Host: GitHub
- URL: https://github.com/falm/attribute-depends-calculator
- Owner: falm
- Created: 2016-07-13T05:56:32.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2017-12-20T02:43:24.000Z (almost 7 years ago)
- Last Synced: 2024-09-30T07:21:18.540Z (about 1 month ago)
- Topics: activerecord, activerecord-callbacks, calculator, rails
- Language: Ruby
- Homepage:
- Size: 31.3 KB
- Stars: 41
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Attribute Depends Calculator
[](https://travis-ci.org/falm/attribute-depends-calculator) [](https://coveralls.io/github/falm/attribute-depends-calculator?branch=master) [](https://codeclimate.com/github/falm/attribute-depends-calculator) [](https://gemnasium.com/github.com/falm/attribute-depends-calculator) [](https://badge.fury.io/rb/attribute-depends-calculator)
The scenario of the gem is when you have an attribute on model that value depends of a calculation of other model's attribute which attribute's model related. AttributeDependsCalculator will help you solve the case
## Requirements
1. Ruby **2.0+**
2. Rails **4.0+**
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'attribute-depends-calculator'
```
And then execute:
$ bundle
## Usage
Assume you have model order and order-item
```ruby
class Order < ActiveRecord::Base
has_many :order_items
depend total_price: {order_items: :price}
end
class OrderItem < ActiveRecord::Base
belongs_to :order
end
```
And you can
```ruby
order = Order.first
order.total_price
#=> 100.0
order.order_items.pluck(:price)
#=> [50.0, 50.0]
order_item = order.order_items.first
order_item.update(price: 100)
order.reload.total_price
#=> 150.0
```
As above show the price of order automatically update when whatever order_items changes
## Advanced
The options **operator** had two cateogries of value, the default value of the gem is expression **sum**
#### Operation
```ruby
class Order < ActiveRecord::Base
has_many :order_items
depend total_price: {order_items: :price, operator: :+} # or :*
end
```
#### Expression
The following expression can be use to calculate the collection of depends attributes
**sum**
```ruby
class Order < ActiveRecord::Base
...
depend total_price: {order_items: :price, operator: :sum} # default
end
```
**average**
```ruby
class Order < ActiveRecord::Base
...
depend avg_price: {order_items: :price, operator: :average}
end
```
**count**
```ruby
class Order < ActiveRecord::Base
...
depend order_items_count: {order_items: :price, operator: :count}
end
```
**minimum**
```ruby
class Order < ActiveRecord::Base
...
depend min_price: {order_items: :price, operator: :minimum}
end
```
**maximum**
```ruby
class Order < ActiveRecord::Base
...
depend max_price: {order_items: :price, operator: :maximum}
end
```
**Proc**
Proc can be passing in operator option, and the only one params is the active reload of the depended relate Model
```ruby
class Order < ActiveRecord::Base
...
depend discount_price: {order_items: :price, operator: -> (items) { items.sum(:price) * discount } }
end
```
## Contributing
Bug reports and pull requests are welcome [on GitHub](https://github.com/falm/attribute-depends-calculator)
## License
MIT © [Falm](https://github.com/falm)