How do I convert an integer to binary in JavaScript?
function dec2bin(dec) { return (dec >>> 0).toString(2);}console.log(dec2bin(1)); // 1console.log(dec2bin(-1)); // 11111111111111111111111111111111console.log(dec2bin(256)); // 100000000console.log(dec2bin(-256)); // 11111111111111111111111100000000You can use Number.toString(2) function, but it has some problems when representing negative numbers. For example, (-1).toString(2) output is "-1".
To fix this issue, you can use the unsigned right shift bitwise operator (>>>) to coerce your number to an unsigned integer.
If you run (-1 >>> 0).toString(2) you will shift your number 0 bits to the right, which doesn't change the number itself but it will be represented as an unsigned integer. The code above will output "11111111111111111111111111111111" correctly.
This question has further explanation.
-3 >>> 0(right logical shift) coerces its arguments to unsigned integers, which is why you get the 32-bit two's complement representation of -3.
Try
num.toString(2);The 2 is the radix and can be any base between 2 and 36
source here
UPDATE:
This will only work for positive numbers, Javascript represents negative binary integers in two's-complement notation. I made this little function which should do the trick, I haven't tested it out properly:
function dec2Bin(dec){ if(dec >= 0) { return dec.toString(2); } else { /* Here you could represent the number in 2s compliment but this is not what JS uses as its not sure how many bits are in your number range. There are some suggestions https://stackoverflow.com/questions/10936600/javascript-decimal-to-binary-64-bit */ return (~dec).toString(2); }}I had some help from here