Negative numbers to binary string in JavaScript

javascript numbers tostring
fernandosavio picture fernandosavio · Apr 22, 2013 · Viewed 18.6k times · Source

Anyone knows why javascript Number.toString function does not represents negative numbers correctly?

//If you try
(-3).toString(2); //shows "-11"
// but if you fake a bit shift operation it works as expected
(-3 >>> 0).toString(2); // print "11111111111111111111111111111101"

I am really curious why it doesn't work properly or what is the reason it works this way? I've searched it but didn't find anything that helps.

Answer

Steve Wang picture Steve Wang · Apr 22, 2013

-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.

http://en.wikipedia.org/wiki/Two%27s_complement

http://en.wikipedia.org/wiki/Logical_shift

Related questions

Validate decimal numbers in JavaScript - IsNumeric()

What's the cleanest, most effective way to validate decimal numbers in JavaScript? Bonus points for: Clarity. Solution should be clean and simple. Cross-platform. Test cases: 01. IsNumeric('-1') => true 02. IsNumeric('-1.5') => true 03. IsNumeric('0') => true 04. …

Read More
How to print a number with commas as thousands separators in JavaScript

I am trying to print an integer in JavaScript with commas as thousands separators. For example, I want to show the number 1234567 as "1,234,567". How would I go about doing this? Here is how I am doing it: function numberWithCommas(x) { …

Read More
How do I check that a number is float or integer?

How to find that a number is float or integer? 1.25 --> float 1 --> integer 0 --> integer 0.25 --> float

Read More