从十六进制字符串获取原始十六进制

Question

I've spend the last few hours researching, but couldn't find anything suiting my needs.

I need to send escaped hex values to a device via TCP, like this:

var char = "\x14";

Now i need to get the size of a string and convert it in escaped hex, like the above, dynamically.

Converting from decimal is easy of course:

var string = "qwertzuiopasdfghjkly"; //Length 20
var hex = (string.length).toString(16); //Returns 14

I've tried it via non-displayable ASCII characters:

char = String.fromCharCode(hex);

But that doesn't return the same as

char = "\x14";

Already found the solution in other languages, but not JavaScript ...

Answer 1

As it turned out, i was looking for String.fromCodePoint() , a relatively new function, specified in ECMAScript 2015. I also had to use utf8 Encoding to make it work.

var string = "qwertzuiopasdfghjkly"; //Length 20
var char = String.fromCodePoint(string.length) // Equivalent to char = "\x14";

More information: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint