How to avoid short-circuit evaluation on
-
20-08-2019 - |
Question
I'm working with Ruby on Rails and would like to validate two different models :
if (model1.valid? && model2.valid?)
...
end
However, "&&" operator uses short-circuit evaluation (i.e. it evaluates "model2.valid?" only if "model1.valid?" is true), which prevents model2.valids to be executed if model1 is not valid.
Is there an equivalent of "&&" which would not use short-circuit evaluation? I need the two expressions to be evaluated.
Solution
Try this:
([model1, model2].map(&:valid?)).all?
It'll return true if both are valid, and create the errors on both instances.
OTHER TIPS
& works just fine.
irb(main):007:0> def a
irb(main):008:1> puts "a"
irb(main):009:1> false
irb(main):010:1> end
=> nil
irb(main):011:0> def b
irb(main):012:1> puts "b"
irb(main):013:1> true
irb(main):014:1> end
=> nil
irb(main):015:0> a && b
a
=> false
irb(main):016:0> a & b
a
b
=> false
irb(main):017:0> a and b
a
=> false
How about:
if [model1.valid?,model2.valid?].all?
...
end
Works for me.
Evaluate them separately and store the result in a variable. Then use a simple && between those booleans :)
Instead of creating an extra array with map, you can pass a block to all?
.
[model_instance_1, model_instance_2].all? {|i| i.valid? }
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