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

Read More

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.

Read More

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

Read More

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

Read More

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.

Read More