Dump byte array as hexadecimal values

Question

In JavaScript on Firefox, a Uint8Array shows like this on the console, using console.log:

Uint8Array […]
0: 131
1: 165
2: 116
3: 111
4: 112

How can I make it show as hexadecimal values, like this:

Uint8Array […]
0: 0x83
1: 0xa5
2: 0x74
3: 0x6f
4: 0x70

I'm trying to debug some websocket communication and have to look up the bytes in the format specification which only lists the values in hex.

Pointy · Accepted Answer · 2018-05-09 17:55:52Z

5

You can't make the console do that (at least I know of no way to do that), but you could transform the array explicitly:

console.log([].map.call(yourArray, x => x.toString(16))

edit — thanks for the correction; the typed arrays return new typed arrays from their .map().

You could also make it a regular array with Array.from().

edited May 9, 2018 at 17:55

answered May 9, 2018 at 17:41

Pointy

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3 Comments

ygoe Over a year ago

Using this, all values that have letters in their hex value are converted to 0. And the type remains a Uint8Array, not some string array. Trying to find the bug.

ygoe Over a year ago

Doesn't work with TypedArray because their map creates another typed array.

Pointy Over a year ago

@ygoe right that or just using the "normal" map version from plain arrays

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