Refactoring Ruby

Question

I have three arrays, two of which come from JSON.

I need to check if each array is not nil and the count is greater than 0. If any are greater than 0 display "Hello World" else display "Boo".

<% if [email protected]? && @arrayOne.count > 0 || !@user_json[:user_stuff].nil? && @user_json[:user_stuff].count > 0 || !@user_json[:more_user_stuff].nil? && @user_json[:more_user_stuff].count > 0 %>
<h1>Hello World</h1>
  <% else %>
<h1>Boo</h1>
<% end %>

I need some help refactoring this code and would like to learn other ways to approach this.

the Tin Man · Accepted Answer · 2015-12-16 16:25:12Z

5

You can use array.blank? (assuming you're using Rails of course) to check whether an array is nil or empty, such as:

<% if [email protected]? || !@user_json[:user_stuff].blank? || !@user_json[:more_user_stuff].blank? %>

Rule of thumb you should move as much logic to the controller as you can.

As suggested in the comments, you can also use present?, which is the same as !blank?, improving readability a bit:

<% if @arrayOne.present? || @user_json[:user_stuff].present? || @user_json[:more_user_stuff].present? %>

edited Dec 16, 2015 at 16:25

the Tin Man

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answered Dec 16, 2015 at 15:29

Leo Brito

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5 Comments

falsetru Over a year ago

If the @arrayOne is nil, this will throw NoMethodError: undefined method 'blank?' for nil:NilClass. (Same for @user_json[:user_stuff], @user_json[:more_user_stuff])

Leo Brito Over a year ago

@falsetru do you mean if @arrayOne etc are undefined? AFAIK blank? tests for nil before testing empty, such that nil.blank? returns true.

Leo Brito Over a year ago

@falsetru blank? is a Rails API function, not a Ruby core function. Calling blank? in irb will in fact result in the undefined error.

spickermann Over a year ago

!foo.blank? could be written as foo.present?. What reads much nice IMHO.

the Tin Man Over a year ago

It's not necessary to use Rails to take advantage of blank? or present?. See stackoverflow.com/questions/4238867/….

falsetru · Accepted Answer · 2015-12-16 15:32:45Z

3

You can use Enumerable#all?:

<% if [!@arrayOne, @user_json[:user_stuff], @user_json[:more_user_stuff]].all? { |x|
  x && x.count > 0
} %>
  ...

answered Dec 16, 2015 at 15:32

falsetru

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Comments

spickermann · Accepted Answer · 2015-12-16 15:57:33Z

1

I would start with something like this:

if [@arrayOne, @user_json[:user_stuff], @user_json[:more_user_stuff]].any?(&:present?)

In a next step I would move that condition into a helper with a nice name. Unfortunately you did not provide why you need this check (that why would hint a good name). But as an idea:

# in a helper
def something_to_show?
  [ @arrayOne, @user_json[:user_stuff], @user_json[:more_user_stuff]
  ].any?(&:present?)
end

# in the view
<% if something_to_show? %>
  <h1>Hello World</h1>
<% else %>
  <h1>Boo</h1>
<% end %>

answered Dec 16, 2015 at 15:57

spickermann

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Comments

the Tin Man · Accepted Answer · 2020-01-28 18:26:01Z

0

A simple way that doesn't require Rails:

puts [a, b, c].map(&:to_a).all?(&:empty?) ? 'Boo' : 'Hello World'

edited Jan 28, 2020 at 18:26

the Tin Man

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answered Dec 16, 2015 at 23:52

pguardiario

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