CODEWITHSUNDEEP
rubyruby-on-rails-3.2erb
Ecnalyr
Ecnalyr

Reputation: 5802

How to efficiently check if a value passed to a view is nil or empty

I have the following code in my application.erb file:

<%= hidden_div_if(@cart.line_items.empty?, :id => "cart") do %>

This works fine unless I load a page that does not receive the @cart.line_items object, when I receive the following error:

undefined method `line_items' for nil:NilClass

How do I rewrite the line from my .erb file to have it behave the same if @cart.line_items is empty and if @cart is nil?

Based on the below answers, I changed my code to use:

<%= hidden_div_if([email protected]? && @cart.line_items.empty?, :id => "cart") do %>

*Updated to match the comment Baldrick added to this question (as it is more concise than my original edit).

Upvotes: 2

Views: 1059

Answers (3)

sawa
sawa

Reputation: 168249

<%= hidden_div_if(@cart.to_a.line_items.empty?, :id => "cart") do %>

Upvotes: 0

Salil
Salil

Reputation: 47532

Use blank? method of Object class.

An object is blank if it‘s false, empty, or a whitespace string. For example, "", " ", nil, [], and {} are blank. For example

 [].blank? #true
 "".blank? #true
 "       ".blank? #true
 false.blank? #true
 {}.blank? #true
 nil.blank? #true

Upvotes: 1

rohit89
rohit89

Reputation: 5773

Use @cart.blank? to check whether it is nil or empty. The blank? method is a rails extension.

Upvotes: 2

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