TILs - Fueling Curiosity, One Insight at a Time

At Codemancers, we believe every day is an opportunity to grow. This section is where our team shares bite-sized discoveries, technical breakthroughs and fascinating nuggets of wisdom we've stumbled upon in our work.

Published
Author
user-image
Syed Sibtain
System Analyst
In Rails, default_scope is a way to automatically apply a query condition to every query for a model.
When we define a default_scope, it always gets added unless we manually remove it.

Example:

Ruby

default_scope { order(created_at: :asc) }


This ensures a consistent ordering across the app without needing to manually add .order(created_at: :asc) every time.
It's especially useful when displaying comments, messages, tasks, or anything that should appear in the order they were created.

Caution:
default_scope can sometimes be annoying if we want a different order temporarily.
In that case, we would need to call .unscope(:order) to remove it manually.

#rubyonrails
Published
Author
user-image
Nived Hari
System Analyst
Instead of manually checking if a key exists in a hash, you can just say:


Ruby

counts = Hash.new(0)


Now whenever you do:


Code

counts[:apple] += 1


Ruby will assume counts[:apple] starts at 0, so no errors — just clean, readable code.

#ruby
Published
Author
user-image
Syed Sibtain
System Analyst
Traits are reusable groups of attributes that we can apply to factories conditionally.
They help avoid duplication and let us customise factories based on different test scenarios.


We can define a trait inside a factory block using the trait keyword


Code

FactoryBot.define do
  factory :user do
    name { "John Doe" }

    trait :admin do
      role { "admin" }
    end

    trait :with_profile_picture do
      after(:build) do |user|
        user.profile_picture.attach(
          io: File.open(Rails.root.join('spec/fixtures/files/test.jpg')),
          filename: 'test.jpg',
          content_type: 'image/jpeg'
        )
      end
    end
  end
end


And then we can use them in our specs. And traits can override any attribute defined in the factory


Code

create(:user, :with_profile_picture)
create(:user, :admin, :with_profile_picture)


#CU6U0R822 #rspec
Published
Author
user-image
Syed Sibtain
System Analyst
define_singleton_method dynamically adds a method to a single object instance without modifying the class itself. This is useful when you need custom behaviour for an individual object at runtime.

It only modifies the behaviour of a single object in memory at runtime. It does not persist any changes to the database or schema.


Ruby

user = User.new(name: "Sibtain")

user.define_singleton_method(:greet) do
  "Hello, my name is #{name}!"
end

puts user.greet # => "Hello, my name is Sibtain"


#CU6U0R822
Published
Author
user-image
Nived Hari
System Analyst
PostgreSQL's jsonb type stores structured JSON data efficiently. Unlike json, it's binary-optimized, supports indexing, and queries faster.
🔹 Why Use jsonb?
• Stores structured data in a single column.
• Faster queries (no reparsing needed).
• Supports indexing for quick lookups.
• Flexible schema—great for dynamic data.
• Allows key-value updates without rewriting the whole object.
• Removes duplicate keys automatically.
jsonb gives you NoSQL flexibility with SQL power! 🚀

#postgres
Published
Author
user-image
Puneeth kumar
System Analyst
Aliasing in Ruby
Aliasing in Ruby helps to eliminate code repetition by providing an alternative name for an existing method, allowing it to be called in different ways without duplicating the logic.
For example,

Ruby

module QuestionsHelper
  def can_modify_question?(question)
    !question.survey.has_answers?
  end

  alias_method :can_edit_question?, :can_modify_question?
  alias_method :can_delete_question?, :can_modify_question?
end


#ruby #aliasing
Published
Author
user-image
Nived Hari
System Analyst
Turbo provides a built-in way to show a loading state on form submission using the turbo_submits_with attribute! 🚀
Instead of manually handling the button's disabled state or adding a spinner, you can simply use:


Code

<%= form.submit t("post.create"), 
  data: { turbo_submits_with: t('loading.saving') } %>


• When the form is submitted, Turbo automatically
replaces the button text with the value provided in turbo_submits_with (e.g., "Saving...").

• Button is also disabled until the request completes.
• Once the request completes, the button reverts to its original text.
No extra JavaScript needed! 🎉

This is a great way to enhance UX with minimal effort. #Rails #Turbo #TIL
Published
Author
user-image
Satya
while using form.number_field in rails if we enter a floating point value eg: 23.45 then browser default validation kicks in syaing: Please enter a valid value. The two nearest valid values are 23 & 24 .
In order to allow the floating point value we can add form.number_field, step: "0.01" . Then we can add upto two decimal point vlaue.

#CU6U0R822 #form-tag-helper
Published
Author
user-image
Satya
to terminate google chrome sessions -> pkill -9 "Google Chrome" .
#terminate-session
Published
Author
user-image
Satya
Ruby Heredoc Syntax & Rails .squish method:
• Bad - Regular heredoc (<<) keeps all whitespace

Ruby

query = <<SQL
    SELECT *
    FROM users
SQL
# Result: "    SELECT *\n    FROM users\n"


• Good - Squiggly heredoc (<<) removes leading whitespace

```
query = <<SQL
SELECT *
FROM users
SQL
# Result: "SELECT \nFROM users\n"
```

• *Best - Rails .squish removes all extra whitespace/newlines

sql

query = <<~SQL.squish
    SELECT *
    FROM   users
    WHERE  active = true
SQL
# Result: "SELECT * FROM users WHERE active = true"


#ruby-heredoc #rails-squish

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