This README is the one indexed from the repository at its latest ref, not from the tag for this version.

truthy

Truthy patches all objects in crystal with a to_b (to boolean) method that will intelligently return a boolean based on the value of the object. This will differ from !!(expr) in a number of cases including the handling of "" and '\0' as false, and proper handling of class instances and arrays (an empty array => false, an array with elements => true).

expr.to_b will always return true or false no matter what you pass to it. !!(expr) is used as a fallback for any language features that are not explictly covered.

An alias is provided so that you can also use *.truthy? if you think this makes more sense than to_b. Both methods function in exactly the same way and are interchangable.

Installation

Add this to your application's shard.yml:

dependencies:
  truthy:
    github: sam0x17/truthy

Usage

require "truthy"

# Booleans
true.to_b # => true
false.to_b # => false

# Objects
nil.to_b # => false
SomeClass.new.to_b # => true

# Strings / Characters
"".to_b # => false
"hey".to_b # => true
'\0'.to_b # => false
'c'.to_b # => true
"0".to_b # => false
"1".to_b # => true
"200".to_b # => true
"1.0".to_b # => true
"-1.0".to_b # => false
"true".to_b # => true
"false".to_b # => false
"yes".to_b # => true
"no".to_b # => false
"nil".to_b # => false
"null".to_b # => false
"none".to_b # => false
"True".to_b # => true
"[]".to_b # => false
"{}".to_b # => false


# Integers
0.to_b # => false
-1.to_b # => false
1.to_b # => true
10.to_b # => true
0_i64.to_b # => false
1_i8.to_b # => true
-1_i16.to_b # => false
0_u64.to_b # => false
3_u16.to_b # => true

# Floats
0.0.to_b # => false
1.0.to_b # => true
0.001.to_b # => true
-0.001.to_b # => false
-1.0.to_b # => false
23.342.to_b # => true

# Arrays
[1, 2, 3].to_b # => true
([] of Int32).to_b # => false

# truthy? alias
true.truthy? # => true
false.truthy? # => false
0.truthy? # => false
1.truthy? # => true