微信小程序socket接口封装

export class WrappedWxSocket {

    static CONNECTING = 0;
    static OPEN = 1;
    static CLOSING = 2;
    static CLOSED = 3;

    constructor(url, protocols) {
        // FIXME 小程序接口与标准 Websocket 对象不完全一致，因此要做兼容处理

        const options = {
            url,
            protocols: typeof protocols === "string" ? [protocols] : protocols,
        };

        this.socketOptions = options;
        this.url = url;
        this.protocols = options.protocols;
        this.socketTask = wx.connectSocket(options);
        this.syncReadyState();

        this.onOpenCallback = function () { };
        this.socketTask.onOpen(event => {
            this.syncReadyState();
            this.onOpenCallback.call(this, event);
        });

        this.onErrorCallback = function () { };
        this.socketTask.onError(error => {
            this.syncReadyState();

            // hack: 标准websocket在连接失败的时候会先触发error再触发close，
            // 但微信小程序则只会触发error，为了保证socket在出了问题后能及时重连，这里手动触发一次close
            setTimeout(() => {
                this.onCloseCallback();
            }, 0);

            this.onErrorCallback.call(this, error);
        });

        this.onMessageCallback = function () { };
        this.socketTask.onMessage(data => {
            this.syncReadyState();
            this.onMessageCallback.call(this, data);
        });

        this.onCloseCallback = function () { };
        this.socketTask.onClose(event => {
            this.syncReadyState();
            this.onCloseCallback.call(this, event);
        });
    }

    syncReadyState() {
        this.readyState = this.socketTask.readyState;
    }

    set onopen(callback) {
        this.onOpenCallback = callback;
    }

    get onopen() {
        return this.onOpenCallback;
    }

    set onerror(callback) {
        this.onErrorCallback = callback;
    }

    get onerror() {
        return this.onErrorCallback;
    }

    set onmessage(callback) {
        this.onMessageCallback = callback;
    }

    get onmessage() {
        return this.onMessageCallback;
    }

    set onclose(callback) {
        this.onCloseCallback = callback;
    }

    get onclose() {
        return this.onCloseCallback;
    }

    close() {

        if (this.socketTask.readyState < 2) {
            this.socketTask.close();
        }
        this.syncReadyState();
    }

    send(data) {
        this.socketTask.send({
            data,
        });
        this.syncReadyState();
    }

}