Implement FileReaderSync

This would solve…

Currently I am doing something that involves keeping everything out of Promise land, however requires reading a Blob

The implementation should look like…

Should look much like the FileReader however have sync behavior. https://developer.mozilla.org/en-US/docs/Web/API/FileReaderSync

I have also considered…

Currently attempting to make a workaround with the given FileReader available with Unidici as of now.

Additional context

ex.

function mockFormDataToString(this: FormData) {
	const entries = [];
	for (const [key, value] of this.entries()) {
		if (value instanceof Blob) {
			const reader = new FileReaderSync();
			reader.readAsText(value);
			const result = reader.result;

			entries.push([key, result]);
		} else {
			entries.push([key, value]);
		}
	}
	return JSON.stringify({
		__formdata: entries,
	});
}

[jimmywarting]

I may have a solution up my sleeve. just going to try it out first

Update: looking good so far… just one more sec to tidy up things.

[KhafraDev]

Here’s an alternative way that does the bare minimum:

index.js

const { Worker, receiveMessageOnPort } = require('worker_threads')
const { join } = require('path')

const blob = new Blob([Buffer.alloc(2 ** 31 - 1).fill('abcdefg')])

const shared = new SharedArrayBuffer(4)
const { port1: localPort, port2: workerPort } = new MessageChannel()

const path = join(__dirname, 'worker.mjs')

const w = new Worker(path, {
  workerData: { shared, blob, port: workerPort },
  transferList: [workerPort]
})

const int32 = new Int32Array(shared)
Atomics.wait(int32, 0, 0)

const { message } = receiveMessageOnPort(localPort)

console.log(message)

worker.mjs

import { workerData } from 'worker_threads'

const { shared, blob, port } = workerData

port.postMessage({
    body: await blob.arrayBuffer()
})

const int32 = new Int32Array(shared)
Atomics.notify(int32, 0)