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50 lines
1.5 KiB
JavaScript

8 months ago
import { ERROR_PACKET, PACKET_TYPES_REVERSE } from "./commons.js";
import { decode } from "./contrib/base64-arraybuffer.js";
const withNativeArrayBuffer = typeof ArrayBuffer === "function";
const decodePacket = (encodedPacket, binaryType) => {
if (typeof encodedPacket !== "string") {
return {
type: "message",
data: mapBinary(encodedPacket, binaryType)
};
}
const type = encodedPacket.charAt(0);
if (type === "b") {
return {
type: "message",
data: decodeBase64Packet(encodedPacket.substring(1), binaryType)
};
}
const packetType = PACKET_TYPES_REVERSE[type];
if (!packetType) {
return ERROR_PACKET;
}
return encodedPacket.length > 1
? {
type: PACKET_TYPES_REVERSE[type],
data: encodedPacket.substring(1)
}
: {
type: PACKET_TYPES_REVERSE[type]
};
};
const decodeBase64Packet = (data, binaryType) => {
if (withNativeArrayBuffer) {
const decoded = decode(data);
return mapBinary(decoded, binaryType);
}
else {
return { base64: true, data }; // fallback for old browsers
}
};
const mapBinary = (data, binaryType) => {
switch (binaryType) {
case "blob":
return data instanceof ArrayBuffer ? new Blob([data]) : data;
case "arraybuffer":
default:
return data; // assuming the data is already an ArrayBuffer
}
};
export default decodePacket;