How can I convert an integer to hex with a fix length in Javascript?

问题

I want to convert an Integer to a hex-string with a fix length in JavaScript

For example I want to convert 154 to hex with a length of 4 digits (009A). I can't figure out a proper way to do that.

回答1:

Number.prototype.toString() can convert a number to hexadecimal when 16 is passed as the argument (base 16):

new Number(154).toString(16) //'9A'

However, this will not have leading zeroes. If you wish to prepend the leading zeroes you can provide a string of 4 zeroes '0000' to concatenate with '9A', then use slice to grab just the last 4 characters:

var value = 154;
var hex = ('0000' + value.toString(16).toUpperCase()).slice(-4); //009A

The sequence of events is displayed like this:

154 -> '9a' -> '9A' -> '00009A' -> '009A'

回答2:

You could add some zeroes and use String#slice for the stringed number.

var value = 154,
    string = ('0000' + value.toString(16).toUpperCase()).slice(-4);
    
console.log(string);

来源：https://stackoverflow.com/questions/42368797/how-can-i-convert-an-integer-to-hex-with-a-fix-length-in-javascript