ltgcgo/mint

"use strict";

// Deno API shim

let upgradeWebSocket = function (request) {
    let [client, socket] = Object.values(new WebSocketPair());
    socket.accept();
    let addEL = socket.addEventListener;
    Object.defineProperty(socket, "addEventListener", {value: function (type, ...args) {
        if (type == "open") {
            args[0].call(socket);
        } else {
            addEL.call(socket, type, ...args);
        };
    }});
    return {
        socket: socket,
        response: new Response(null, {
            status: 101,
            webSocket: client
        })
    };
};

let Deno = {
    upgradeWebSocket
};

// Other shims

let WebSocket = class {
    #target = {
        onclose: [],
        onerror: [],
        onmessage: [],
        onopen: [],
        close () {},
        readyState: 0,
        isDummy: true
    };
    #url = "";
    #getWsObj = async function (url) {
        let upThis = this;
        let timeout = AbortSignal.timeout(5000);
        let reply;
        let failure = function () {
            let error = new Error("Bad WebSocket handshake");
            upThis.#target?.onerror?.forEach(function (e) {
                e[0](error);
            });
            upThis.#target?.onclose?.forEach(function (e) {
                e[0]();
            });
        };
        timeout.addEventListener("abort", function () {
            if (!reply || reply?.readyState != 1) {
                failure();
            };
        });
        reply = await fetch(url, {
            headers: {
                "Upgrade": "websocket"
            }
        });
        let handle = reply.webSocket;
        if (handle) {
            this.#target.onclose.forEach(function (e) {
                handle.addEventListener("close", ...e);
            });
            this.#target.onerror.forEach(function (e) {
                handle.addEventListener("error", ...e);
            });
            this.#target.onmessage.forEach(function (e) {
                handle.addEventListener("message", ...e);
            });
            this.#target.onopen.forEach(function (e) {
                handle.addEventListener("open", ...e);
            });
            handle.addEventListener("error", function () {
                handle.close();
            });
            handle.accept();
            this.#target = handle;
        } else {
            failure();
        };
    };
    addEventListener(...args) {
        if (this.#target.isDummy) {
            this.#target[`on${args[0]}`].push(args.slice(1));
        } else {
            this.#target?.addEventListener(...args);
        };
    };
    close(...args) {
        this.#target.close(...args);
    };
    send(...args) {
        this.#target?.send(...args);
    };
    get url() {
        return this.#url;
    };
    get readyState() {
        return this.#target.readyState;
    };
    constructor(url) {
        let wsTarget = url,
        protIdx = url.indexOf("ws");
        if (protIdx == 0) {
            wsTarget = url.replace("ws", "http");
        };
        this.#url = wsTarget;
        this.#getWsObj(wsTarget);
    };
};

export {
    Deno,
    WebSocket
};