js how to parse HEX properly / fffd - javascript

Having a problem here. I recieve data from hardware as HEX numbers. I use this to make them into strings(it is intended):
arr.push(data.charCodeAt(0).toString(16))
It works well. For example I recieve 0x00 and this code correctly adds a '0' string to the array.
But there is a problem. JS automatically understands these codes as symbols. And when I try 0xAA or 0x80 I recieve FFFD. As I understand. it means that there is no such symbol in utf-8.
How do I make js understand my data as hex-numbers, but not as symbol codes?
Edit: I figured out that my problem was in my wrong way of using the library which recieved data from hardware.


Just convert the Hex number to decimal
yourNumber = parseInt(hexString, 16);


To convert hexadecimal to decimal you can use the next function:
parseInt(hexValue, 16)
Hope this helps :)
data = '0XAA'
data1 = '0X80'
console.log( parseInt(data, 16))
console.log( parseInt(data1, 16))


Okay, I figured out that my problem was in a library I used to recieve data

Related

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So, I am trying to turn a number to binary, which seems fine in both javascript and python, but my issue is that when I do so, they both return a different binary string.
I enter: 585190997647163394
JavaScript returns: 100000011111000001000001110010100100100001000000000000000000
Python returns: 100000011111000001000001110010100100100001000000000000000010
If you can´t see the difference, the penultimate digit in the string python has returned is a 1 instead of a 0, like in the javascript string.
Please explain to me how this can happen/how to fix it.
Thank you!
Here is the code if needed:
js:
var bin = (+in).toString(2);
console.log(bin);
py:
print(bin(int(input("bingledingle >"))))

JavaScript uses floating point numbers with double precision. 585190997647163394 is too large.
585190997647163394 > Number.MAX_SAFE_INTEGER
The number is rounded to 585190997647163392.
You can use BigInt instead.
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var decoded = {};
function Decoder(bytes, port) {
if (port == 1) {
decoded.test = bytes[0];
}
return decoded;
}
And this is the output I get:
{
"test": 124
}

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