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javascriptreturnoperator-precedence
Peter Klipfel
Peter Klipfel

Reputation: 5178

Javascript return var++

So I'm wondering why 

var x=5
function foo(){
  return x++
}
foo()

returns 5 and 

var x=5
function foo(){
  return ++x
}
foo()

returns 6.

Is it because the precedence of the ++ operator excludes it from being executed before the return - ie. the precedence is (return x)++? Or is there something tricky going on?

Upvotes: 1

Views: 5146

Answers (1)

Austin Brunkhorst
Austin Brunkhorst

Reputation: 21130

It's pre/post increment. It's just how the operators work. ++var is pre increment which means the value is incremented before returning and var++ is post increment, where the value is incremented after returning.

You can find more details about these semantics here.

Upvotes: 8

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