Sometimes from network transmissions/usdb devices you receive the data has a hexadimal string eg:
"12ADFF1345"
These type of string I want somehow to be converted into a binary equivalent into a buffer, in order to perform a some mathematical or binary operations on them.
Do you know how I can achieve that?
Use the builtin Buffer class :
let buf1 = Buffer.from('12ADFF1345', 'hex');
let value = buf1.readInt32LE(0);
let value2 = buf1.readInt16LE(2);
console.log(value,value2);
>> 335523090 5119
// '13ffad12' '13FF' (LE)
>> 313392915 -237
// '12ADFF13' 'ff13' (BE)
https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_string_encoding
Yes I know how to do that, the algorithm is simple (assuming that you have no escape characters):
0x^first_character_pair^In other words consult the following code:
const hexStringToBinaryBuffer = (string) => {
const subStrings = Array.from(string);
let previous = null;
const bytes = [];
_.each(subStrings, (val) => {
if (previous === null) { // Converting every 2 chars as binary data
previous = val;
} else {
const value = parseInt(`0x${previous}${val}`, 16);
bytes.push(value);
previous = null;
}
});
return Buffer.from(bytes);
};
This is usefull if you pass as string the result of a Buffer.toString('hex') or equivalent method via a network socket or a usb port and the other end received it.
