expo
Version:
50 lines • 2.3 kB
TypeScript
/**
* A message frame packer that serializes a messageKey and a payload into either a JSON string
* (fast path) or a binary format (for complex payloads).
*
* Fast Path (JSON.stringify/JSON.parse):
* - For simple payloads (e.g., strings, numbers, null, undefined, or plain objects), the packer
* uses `JSON.stringify` for serialization and `JSON.parse` for deserialization, ensuring
* optimal performance.
*
* Binary Format:
* - For more complex payloads (e.g., Uint8Array, ArrayBuffer, Blob), the packer uses a binary
* format with the following structure:
*
* +------------------+-------------------+----------------------------+--------------------------+
* | 4 bytes (Uint32) | Variable length | 1 byte (Uint8) | Variable length |
* | MessageKeyLength | MessageKey (JSON) | PayloadTypeIndicator (enum)| Payload (binary data) |
* +------------------+-------------------+----------------------------+--------------------------+
*
* 1. MessageKeyLength (4 bytes):
* - A 4-byte unsigned integer indicating the length of the MessageKey JSON string.
*
* 2. MessageKey (Variable length):
* - The JSON string representing the message key, encoded as UTF-8.
*
* 3. PayloadTypeIndicator (1 byte):
* - A single byte enum value representing the type of the payload (e.g., Uint8Array, String,
* Object, ArrayBuffer, Blob).
*
* 4. Payload (Variable length):
* - The actual payload data, which can vary in type and length depending on the PayloadType.
*/
type MessageKeyTypeBase = string | object;
type PayloadType = Uint8Array | string | number | null | undefined | object | ArrayBuffer | Blob;
interface MessageFrame<T extends MessageKeyTypeBase> {
messageKey: T;
payload?: PayloadType;
}
export declare class MessageFramePacker<T extends MessageKeyTypeBase> {
private textEncoder;
private textDecoder;
pack({ messageKey, payload }: MessageFrame<T>): string | Uint8Array | Promise<Uint8Array>;
unpack(packedData: string | ArrayBuffer): MessageFrame<T>;
private isFastPathPayload;
private payloadToUint8Array;
private packImpl;
private deserializePayload;
private static getPayloadTypeIndicator;
}
export {};
//# sourceMappingURL=MessageFramePacker.d.ts.map