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I read Is there a performance difference between i++ and ++i in C?:
Is there a performance difference between i++ and ++i if the resulting value is not used?
What's the answer for JavaScript?
For example, which of the following is better?
1)
for(var i=0;i<max;i++){
//code
}
2)
for(var i=0;i<max;++i){
//code
}
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So === faster than == in Javascript === compares if the values and the types are the same. == compares if the values are the same, but it also does type conversions in the comparison. Those type conversions make == slower than ===.
Equality operator == converts the data type temporarily to see if its value is equal to the other operand, whereas === (the identity operator) doesn't need to do any type casting and thus less work is done, which makes it faster than ==.
Though we can say that the ++i is slightly faster than i++. The i++ takes local copy of the value of i before incrementing, while ++i never does. Sometimes some compiler optimizes the code if possible.
Here is an article about this topic: http://jsperf.com/i-vs-i/2
++i seems to be slightly faster (I tested it on firefox) and one reason, according to the article, is:
with i++, before you can increment i under the hood a new copy of i must be created. Using ++i you don't need that extra copy. i++ will return the current value before incrementing i. ++i returns the incremented version i.
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