Question

我正在尝试在该库中创建 Angular 库；我创建了一个单例类来处理相同的 SignalR 连接，这是我的代码：

import * as signalR from '@microsoft/signalr';

export class SignalRConnection {

    static _instance: SignalRConnection;

    connection: signalR.HubConnection;

    private constructor() {
        this.connection = new signalR.HubConnectionBuilder()
            .withUrl("http://localhost:5000/hub")
            .build();

        // TODO: something on reject
        this.connection.start().catch(console.log);
    }

    /**
     * Get exists or create new instance of SignalR connection
     */
    static getOrCreate(): SignalRConnection {
        if (SignalRConnection._instance == undefined) {
            SignalRConnection._instance = new SignalRConnection();
        }
        return SignalRConnection._instance;
    }
}

此代码在开发过程中按预期方式工作（我使用public-api使用它），但是当我尝试构建程序包时，出现此错误：

error encountered
in metadata generated for exported symbol 'SignalRConnection':
Metadata collected contains an error that will be reported at runtime: Only initialized variables and constants can be referenced because the value
of this variable is needed by the template compiler.

编译时发生了什么变化，我该如何解决？

Answer 1

export class SignalRConnection implements OnInit {

    static _instance: any = null;

   ngOnInit() {
        SignalRConnection._instance= this;
    }
}

为什么用单例类构建Angular包时出错？

1 个答案: