New job! More later on that. They shipped me a company laptop and I wanted to go through and document the essensial tools that I used to get up and running for Ruby and Rails Development.

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all?

The all? method in Ruby returns a boolean value (true/false) if all the objects in the list either return true or satisfies the block condition.

Ruby

Enumerable#all?

No block:

>> [ true, "dog", "bear", 19 ].all?
=> true
>> [ nil, true, "hello" ].all?
=> false

With a block:

>> %w(cat dog squirrel bear).all? { |word| word.length >= 3 }
=> true
>> %w(cat dog squirrel bear).all? { |word| word.length <= 3 }
=> false

Elixir

Enum.all? No block:

>> Enum.all?([ true, "dog", "bear", 19 ])
true
>> Enum.all?([ nil, true, "hello" ])
false

With a block/fn:

>> Enum.all?(["cat", "dog", "squirrel", "bear"], fn word -> String.length(word) >= 3 end)
=> true
>> Enum.all?(["cat", "dog", "squirrel", "bear"], fn word -> String.length(word) <= 3 end)
=> false

Javascript

Array.prototype.every()

Only with callback support:

> [ true, "dog", "bear", 19 ].every(x => x)
true
> [null, true, "hello" ].every(x => x)
false

> ["cat", "dog", "squirrel", "bear"].every(word => word.length >= 3)
true
> ["cat", "dog", "squirrel", "bear"].every(word => word.length <= 3)
false

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I have been working in a legacy codebase and we have been seeing different styles of ruby syntax. I give my nitpicky thoughts about when to use these and why.

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Formatting a Date in JS Without A Library

Most of us who use momentjs and dayjs JavaScript don’t always notice that Javascript has a native Internationalization API that provides some date formatting methods. It is built in. There is no need for an external library.

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Elixir has a very flexible feature called Protocols. These can be used for helper utilities modules.

defprotocol Double do
  def double(input)
end

defimpl Double, for: Integer do
  def double(int) do
    int * 2
  end
end

defimpl Double, for: List do
  def double(list) do
    list ++ list
  end
end

Hoping I can do more on how this can be used in a phoenix app.

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Although it is not super intuitive since it does not belong to the Map module, Elixir has a built in get_in function which is used to retrieve a nested value in nested maps using an array of keys.

movie_map = %{ movie: %{ title: "Deadpool"} }
title = get_in(movie_map, [:movie, :title])
=> nil
# When value is not present, returns nil
description = get_in(movie_map, [:movie, :description])
=> nil
director_name = get_in(movie_map, [:movie, :cast, :director, :first_name])
=> nil

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Elixir has a powerful withconstruct that isn’t availabe in ruby. This is an elegant pattern for a language. It can be used to pull out individual values or it can be chained.

Individual value example (yes, a bit contrived):

def divide(values) do
  with {:ok, dividend} <- Map.fetch(values, :dividend),
       {:ok, divisor} <- Map.fetch(values, :divisor) do
    {:ok, dividend / divisor}
  end
end

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Last year I did podcasts so this year I’ll do music.

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In this article I share how I was able to create a Baby Age Calculator using Phoenix/Elixir LiveView.

If you just want to know how old your child is, jump over to babyweeks.herokuapp.com. If you want to download the source code, goto github.com/monkseal/babyweeks-phx-liveview

LiveView - Phoenix/Elixir’s Javascript killer?

As described here and here — “Phoenix LiveView is an exciting new library which enables rich, real-time user experiences with server-rendered HTML. LiveView powered applications are stateful on the server with bidrectional communication via WebSockets, offering a vastly simplified programming model compared to JavaScript alternatives.”

If you don’t want to write Javascript to have a real-time web application, Phoenix LiveView provides an interesting alternative with server-rendered HTML.

Being one to avoid bold pronouments, I won’t commit myself to say that LiveView will deal a death blow to javascript in your app. For one, you may already have a lot Javascript in your app. Maybe some if you even like. However, if you are interested in managing state on the server, LiveView is quite compelling.

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… That you will probably end up creating yourself …

After over 12 years of working with Ruby on Rails on multiple different codebases, I’ve some common themes. This is my list of patterns or types of objects you will see in Rails applications.

1. Query Objects.

ActiveRecord provides the scope macro which allows us to define queries related to that model. However, for larger, more complex queries that span multiple models, scopes can often lead to a patchwork of distributed logic. To address this, I prefer to build stand alone a Query object. I usually place this in a separate folder: `app/queries’. The following is an example of query object:

A simple base query object:

module Kenglish
  QueryResult = Struct.new(:data, :meta)

  class Query
    class << self
      def result(*args)
        new(*args).result
      end
    end

    attr_reader :params, :relation

    def initialize(params, relation)
      @params = params
      @relation = relation
    end

    def build_result(data, meta)
      QueryResult.new(data, meta)
    end
  end
end

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