browser.js: .compare() unsupported syntax

[cesare-montresor]

To my understanding, it seams that the objects created by b4a.from() don't expose the same signatures as nodejs Buffer leading to potentially non-crossplatform code.
I have no bulletproof idea on how to fix it, however, I wonder if attempting to inject methods to the javascript TypedArray prototype, could deliver a clean solution.

Works on NodeJS, but doesn't on browser.

const b4a = require('b4a')

const buf = b4a.from('a lot of binary data coming from tar file')
const USTAR_MAGIC = b4a.from('ustar\x00')

if ( USTAR_MAGIC.compare(buf, MAGIC_OFFSET, MAGIC_OFFSET + 6) === 0 ){
    console.log("eureka!")
}

src: https://github.com/mafintosh/tar-stream/blob/ca0e270f11dc61f507f7972e53071b8fa99e66bf/headers.js#L265

Works on browser.

const b4a = require('b4a')

const buf = b4a.from('a lot of binary data coming from tar file')
const USTAR_MAGIC = b4a.from('ustar\x00')

const magicBuf = new b4a.alloc(6,0,'hex')
b4a.copy(buf,magicBuf,0,MAGIC_OFFSET, MAGIC_OFFSET + 6)

if ( b4a.compare(USTAR_MAGIC, magicBuf) === 0 ){
    console.log("eureka!")
}

src: https://github.com/cesare-montresor/tar-stream/blob/628855745845fdd3a13d9d99f47253df70223331/headers.js#L265

[mafintosh]

In general, just the b4a functions and only "link" to the uint8arrays methods for node buffers is a great practice

[kasperisager]

Agree with @mafintosh, this is the intended behaviour.