Files
ms/packages/websocket/src/engine.io-parser/encodePacket.ts
2023-02-09 13:49:48 +08:00

32 lines
920 B
TypeScript

import { PACKET_TYPES, Packet, RawData } from "./commons.js";
const encodePacket = (
{ type, data }: Packet,
supportsBinary: boolean,
callback: (encodedPacket: RawData) => void
) => {
if (data instanceof ArrayBuffer || ArrayBuffer.isView(data)) {
const buffer = toBuffer(data);
return callback(encodeBuffer(buffer, supportsBinary));
}
// plain string
return callback(PACKET_TYPES[type] + (data || ""));
};
const toBuffer = data => {
if (Buffer.isBuffer(data)) {
return data;
} else if (data instanceof ArrayBuffer) {
return Buffer.from(data);
} else {
return Buffer.from(data.buffer, data.byteOffset, data.byteLength);
}
};
// only 'message' packets can contain binary, so the type prefix is not needed
const encodeBuffer = (data: Buffer, supportsBinary: boolean): RawData => {
return supportsBinary ? data : "b" + data.toString("base64");
};
export default encodePacket;