• Style
• Syntax

Global Outline

Style

• Use 2 spacing indentation
• Use snake case
• use all caps on constant
• space around operator
• no messy space around (,[,{,},],),!,?,...
• comment wisely
• empty line between different logic
• indent wisely
• align element of array or hash

Syntax

• Prefer "unless" than if !
• Use one line "if" or "unless" when only has 1 line code
• avoid 1 single line method
• put . at the first line when chaining method goes too long
• use "each" instead of "for"
• use ternary if only has 1 line code
• don't mix hash rocket with literal hash
• prefer find instead of where(conditions).first
• use where.not (rails 4) instead of query comparation
• use understandable word
• remove dead code , don't comment it

Rails Outline

• config
• model
• controller
• view
• AR
• database migration
• I18n
• assets
• mailer and jobs

Config

• put constant and gem config in config
• add / remove assets that you want to precompile
• create staging.rb for staging
• use correct routes method (GET, POST, PUT, DELETE)
• use resource and nested resources wisely
• use collection and member for routes

Model

• Make it fat and clean
• separate to another method if it's too long
• DRY or make it as module
• use scope

Controller

• Make it thin and understandable
• Keep application controller clean, use it for global only
• Keep simple logic, if it's too complicated move to model
• use before_action
• follow REST
• use private and public method

View

• Do not change variable in view
• minimal or no logic
• move logic to helper
• separate from assets as much as possible
• use partial for shared views
• don't use too much partial it will slow down your rendering

AR

• Avoid altering default method
• Group your method e.g. validation, scopes, dll
• Use custom validator
• Avoid sql injection vulnerability (string interpolation)
• use find_each for big records

Database Migration

• Always use migration
• Add index if needed
• When it's deployed, don't up/down old migration

I18n

• Make it hierarcy
• Separate for each language

Assets

• Use your own asset grouping (don't require all)
• Use gemified version
• Precompile only css / js you need

Mailer and Jobs

• Name your mailer class with suffix Mailer
• Place your long process in background
• Sending email should be in background
• Style should be inline

That's all from me