When u open up your console and type in any point number for example 5.123 and add | 0 after it, it will be rounded to 5.
Somehow, if u change it to | 2 , it will write down 7.
var test1 = 5.123 | 0 ; // will be 5
var test2 = 5.123 | 2 ; // will be 7
var test3 = 5.123 | 4 ; // will be 5 again
Can someone explain to my what is happening above and also, can I use this instead of parseInt?
It's a bitwise operator... to quote this page:
Bitwise operators treat their operands as a sequence of 32 bits (zeroes and ones), rather than as decimal, hexadecimal, or octal numbers. For example, the decimal number nine has a binary representation of 1001. Bitwise operators perform their operations on such binary representations, but they return standard JavaScript numerical values.
what happens, is that the operator treats the number as a 32 bit integer; so 5.123 is treated as:
0000 0000 0000 0000 0000 0000 0000 0101
(the decimal part is thrown out) and 0 is treated as
0000 0000 0000 0000 0000 0000 0000 0000
then the OR function compares the two, and writes a 1 if either number has a 1. So using the bitwise Or with a decimal number and zeeo is essentially a way to discard the decimal part and retain the integer part.
Your other example with two is:
0000 0000 0000 0000 0000 0000 0000 0101 (5)
0000 0000 0000 0000 0000 0000 0000 0010 (2)
--------------------------------------- ORed
0000 0000 0000 0000 0000 0000 0000 0111 (7)
and the example with 4:
0000 0000 0000 0000 0000 0000 0000 0101 (5)
0000 0000 0000 0000 0000 0000 0000 0100 (4)
--------------------------------------- ORed
0000 0000 0000 0000 0000 0000 0000 0101 (5)
You can use it to convert to discard the decimal part of a number - see Using bitwise OR 0 to floor a number
