JavaScript Incrementing (++)

Download JavaScript for free

Example

The Increment operator (++) increments its operand by one.

  • If used as a postfix, then it returns the value before incrementing.
  • If used as a prefix, then it returns the value after incrementing.

//postfix
var a = 5,    // 5
    b = a++,  // 5
    c = a     // 6

In this case, a is incremented after setting b. So, b will be 5, and c will be 6.


//prefix
var a = 5,    // 5
    b = ++a,  // 6
    c = a     // 6

In this case, a is incremented before setting b. So, b will be 6, and c will be 6.


The increment and decrement operators are commonly used in for loops, for example:

for(var i = 0; i < 42; ++i)
{
  // do something awesome!
}

Notice how the prefix variant is used. This ensures that a temporarily variable isn't needlessly created (to return the value prior to the operation).

Little / Big endian for typed arrays when using bitwise operators