$ curl -X POST -u admin:${PASSWORD} -H "content-type: application/json" https://${YOUR_IP}/rest/file/read --data '{"file":"my-test.backup","chunk-size":"4096","offset":"0"}' | jq
parse error: Unfinished string at EOF at line 1, column 20

SyntaxError: Bad control character in string literal in JSON at position 16

async getBinaryBrokenJSON(url: string, upload: {[key: string]: string | string[] }) : Promise<Buffer>
{
	var response = await fetch(url, {
		method: 'POST',
		body: JSON.stringify(upload),
		headers: {'Authorization': YOUR_AUTH_STRING, 'Content-type': 'application/json'},
	});
	var data_bin = new Uint8Array(await response.arrayBuffer());
	var fixed: number[] = [];
	const append = (b:number) => {
		if (b > 9)
			fixed.push(65 + (b-10)); // 'A'+y
		else
			fixed.push(0x30 | b); // '0'+y
	}
	data_bin.forEach(b => {
		if (b < 0x20 || b >= 0x80)
		{
			fixed.push(0x5c); // '\'
			fixed.push(0x75); // 'u'
			fixed.push(0x30); // '0'
			fixed.push(0x30); // '0'
			append(b >> 4);
			append(b & 0xF);
		}
		else
			fixed.push(b);
	})
	var data = JSON.parse(new TextDecoder("ascii").decode(new Uint8Array(fixed)));
	// check data for error responses here
	return Buffer.from(data[0].data as string, "binary");
}