How to display nodejs raw Buffer data as Hex string

Question

The following code uses SerialPort module to listen to data from a bluetooth connection.

I am expecting to see a stream of data in Hexadecimal format printed in console. But the console just shows some weird simbols. I want to know how can I decode and display the data in console.

var serialPort = new SerialPort("/dev/tty.EV3-SerialPort", {
  parser: SP.parsers.raw
}, false); // this is the openImmediately flag [default is true]

serialPort.open(function () {
 console.log('open');
 serialPort.on('data', function(data) {
   var buff = new Buffer(data, 'utf8'); //no sure about this
  console.log('data received: ' + buff.toString());
 });  
});

data is already a buffer, no need to convert. Then: data.toString('hex'); — Laurent Perrin, Sep 18 '13 at 18:42

score 280 · Accepted Answer · edited Apr 29 '16 at 19:11

280

This code will show the data buffer as a hex string:

buff.toString('hex');

edited Apr 29 '16 at 19:11

Justin

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answered Jul 01 '14 at 07:01

Seryh

3,144
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6

do u know how to do the reverse? – bubakazouba Dec 21 '15 at 23:17
27

bubakazouba: new Buffer( buf.toString('hex'), 'hex' ); – Seryh Dec 23 '15 at 07:33
7

[DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead. So now it should be `Buffer.from( buf.toString('hex'),'hex');` – flob Mar 12 '19 at 12:47
2

It returns for me `[object ArrayBuffer]`? what's wrong? – Mamdouh Saeed Aug 25 '20 at 12:11

score 3 · Answer 2 · edited Nov 29 '18 at 20:57

3

Top answer is the simplest way to do it.

An alternative method:

data = Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);

Array.prototype.map.call(new Uint8Array(data),
               x => ('00' + x.toString(16)).slice(-2))
        .join('').match(/[a-fA-F0-9]{2}/g).reverse().join('');

edited Nov 29 '18 at 20:57

Alexis Wilke

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answered Jul 25 '17 at 19:45

Omar Taylor

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This answer was actually useful for me, because I have to join it with '-' for it to interop with C#. Upvoted. – Edza Mar 31 '20 at 09:12

How to display nodejs raw Buffer data as Hex string

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