Rails-WhereExists.md

Pattern: Inconsistent use of exists?

Issue: -

Description

This rule enforces consistent style when using exists?.

When EnforcedStyle is 'exists' then the rule enforces exists?(…​) over where(…​).exists?. When EnforcedStyle is 'where' then the rule enforces where(…​).exists? over exists?(…​).

Examples

EnforcedStyle: exists (default)

# bad
User.where(name: 'john').exists?
User.where(['name = ?', 'john']).exists?
User.where('name = ?', 'john').exists?
user.posts.where(published: true).exists?

# good
User.exists?(name: 'john')
User.where('length(name) > 10').exists?
user.posts.exists?(published: true)

EnforcedStyle: where

# bad
User.exists?(name: 'john')
User.exists?(['name = ?', 'john'])
User.exists?('name = ?', 'john')
user.posts.exists?(published: true)

# good
User.where(name: 'john').exists?
User.where(['name = ?', 'john']).exists?
User.where('name = ?', 'john').exists?
user.posts.where(published: true).exists?
User.where('length(name) > 10').exists?

Further Reading

• RuboCop - Rails/WhereExists