/**
 * A wire-format strategy used by websocket clients to encode outgoing
 * envelopes and decode incoming ones. Codecs are picked per-client at
 * handshake time via the Sec-WebSocket-Protocol header.
 */
export type Codec = {
    /**
     * - the Sec-WebSocket-Protocol identifier.
     */
    name: string;
    /**
     * - whether encode() produces a binary payload.
     */
    binary: boolean;
    /**
     * - whether this codec's runtime is installed.
     * Lazy/optional codecs (like MessagePack) may be unavailable without breaking imports.
     */
    available: boolean;
    /**
     * - serialize an envelope/object.
     */
    encode: (obj: any) => (string | Buffer);
    /**
     * - deserialize a received envelope.
     */
    decode: (data: Buffer | string) => any;
    /**
     * - cheap check on incoming binary
     * bytes: returns true if they *might* be a control envelope, false if they are
     * definitely raw binary data. JSON codec always returns false (its envelopes
     * never travel on binary frames).
     */
    sniff: (data: Buffer) => boolean;
};
import json = require("./json");
import msgpack = require("./msgpack");
/**
 * A wire-format strategy used by websocket clients to encode outgoing
 * envelopes and decode incoming ones. Codecs are picked per-client at
 * handshake time via the Sec-WebSocket-Protocol header.
 * @typedef Codec
 * @property {string} name - the Sec-WebSocket-Protocol identifier.
 * @property {boolean} binary - whether encode() produces a binary payload.
 * @property {boolean} available - whether this codec's runtime is installed.
 * Lazy/optional codecs (like MessagePack) may be unavailable without breaking imports.
 * @property {(obj: any) => (string|Buffer)} encode - serialize an envelope/object.
 * @property {(data: Buffer|string) => any} decode - deserialize a received envelope.
 * @property {(data: Buffer) => boolean} sniff - cheap check on incoming binary
 * bytes: returns true if they *might* be a control envelope, false if they are
 * definitely raw binary data. JSON codec always returns false (its envelopes
 * never travel on binary frames).
 */
/** @type {Object.<string, Codec>} */
export const codecs: {
    [x: string]: Codec;
};
/**
 * Resolves a subprotocol string to its codec, or null if unsupported or
 * unavailable. An empty / falsy input resolves to the default JSON codec,
 * matching "no Sec-WebSocket-Protocol header" client behavior.
 * @param {string} [subprotocol]
 * @returns {Codec|null}
 */
export function resolve(subprotocol?: string): Codec | null;
export { json, msgpack };