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Predicate Methods

A commonly used definition of a predicate method is a method that returns a boolean value. In Ruby, the convention is to end the method name with a question mark.

A predicate method should return true or false. (In the reference article, the author mentions that some people instead advocate for a ‘truthy’ value.)

0.zero? # => true

1.zero? # => false

defined? in Ruby might appear to be an exception to the convention as it does not return true or false, but defined? an operator, not a method.

In Rails, there is a “getter” method generated for each database column by default, like Item#returns_accepted. As a convenience, a question mark method (Item#returns_accepted?) is also generated for boolean database columns which behaves mostly the same but it also converts nil to false.

references

The Elements of Ruby Style: Predicate Methods

Rails seeds

A seeds file is a great addition to a new Rails project. Seed data will allow you to populate your developing app quickly, and unlike manually entering sample data, a seeds file can be run over and over as you work.

When working on an existing code base, creating seed data is a safe way to learn the data model. And faker can be added to generate data for performance testing.

faker initial seeds replant

# db/seeds.rb
require "faker"

return if Rails.env.production? # in case someone runs db:seed instead of db:seed:replant

10.times do
    User.create!(
    Faker::Name::name,
    password: "Not2secret",
    Faker::Internet.email
    )
end

# Initial creating and seeding of database
$ rails db:seed

# or
$ rails db:seed:replant

references

Rails 6 adds db:seed:replant task

Copilot language translation

In a recent Hackathon, content needed to be translated into multiple languages. Initially, web based translation services were used and a small sample was prepared to be used as a seed file.

It was surprising to find that Github Copilot can help you translate languages!

hindi.phrases.create!(label: "I need assistance", phrase: "मुझे सहायता की ज़रूरत है",
pronunciation: "mujhe sahaayata kee jaroorat hai")
hindi.phrases.create!(label: "Dial 911",
# then tab and Copilot will suggest:
hindi.phrases.create!(label: "Dial 911", phrase: "911 डायल करें", pronunciation: "911 daayal karen")

Much faster than looking up individually and generated 12 translations in 10 languages in minutes.