TypeError when using writeFile of arraybuffer image data type

Question

I'm getting an error when I'm trying to write a file with PNG data.

var png = UPNG.encode([data], width, height, 0);
var file = fs.writeFile("mypng.png", png);

Error:

[TypeError: The "data" argument must be of type string or an instance of Buffer, TypedArray, or DataView. Received an instance of ArrayBuffer

Here is the data and png values:

UPDATE:
The answer provided is correct but I was also needed to pass in the buffer of the UInt8Array.

Before:

var data = UInt8Array(value);
var png = UPNG.encode([data], width, height, 0);
var file = fs.writeFile("mypng.png", png);

After:

var data = UInt8Array(value);
var png = UPNG.encode([data.buffer], width, height, 0);
var buffer = Buffer.from(png);
var file = fs.writeFile("mypng.png", png);

prospector · Accepted Answer · 2022-12-06 02:54:43Z

2

It says you sent an ArrayBuffer but you can only use an instance of a Buffer, TypedArray or DataView

Try converting the ArrayBuffer to a Buffer instance

var data = UInt8Array(value);
var png = UPNG.encode([data.buffer], width, height, 0);
var buffer = Buffer.from(png);
var file = fs.writeFile("mypng.png", buffer);

edited Dec 6, 2022 at 2:54

answered Dec 5, 2022 at 19:03

prospector

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4 Comments

1.21 gigawatts Over a year ago

I have tried that and it gets rid of the error but the png is blank. It does show the correct size in the Finder. If that's the case then it must be the encoder?

prospector Over a year ago

@1.21gigawatts my first thought was permissions to the server, it could be blank if it can't write but you said it's showing the right file size so it must be an issue with corrupted data, have you tried different pngs?

1.21 gigawatts Over a year ago

it was figured out. you are correct to get the buffer from the png data. data was a Uint8array and I needed to pass in the the buffer of that data so data.buffer and it worked.

1.21 gigawatts Over a year ago

I'm marking this as the correct answer because it doesn't work without the code you've shown

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