[英]Typescript Async/Await with SignalR Function
我遇到了一个问题,其中SignalR集线器功能序列无法异步执行。
我有:
//Hub functions
//Initializing hub server and clients.
function HubStart() {
$.connection.hub.start().then(function () {
console.log(1);
return new Promise(resolve => resolve);
});
}
//Hub server-side function that add user's name to chat board.
function HubUserOnline(user: any) {
$.connection.boardHub.server.userOnline(user).then(resolve => { return new Promise(resolve => resolve); });
}
//Main
var viewModel = ko.mapping.fromJS(model, mappingOption);
main();
//Definition of the main function
async function main() {
console.log(0);
await HubStart();
console.log(2);
await HubUserOnline(ko.mapping.toJS(viewModel.CurrentUser))
console.log(3);
}
});
但是,控制台显示:
> 0
> 2
> Uncaught (in promise) Error: SignalR: Connection must be started before data can be sent. Call .start() before .send()
> at hubConnection.fn.init.send (jquery.signalR-2.2.1.js:780)
> at init.invoke (jquery.signalR-2.2.1.js:2734)
> at Object.userOnline (hubs:120)
> at HubUserOnline (WaitingRoom.ts:190)
> at WaitingRoom.ts:203
> at Generator.next (<anonymous>)
> at fulfilled (WaitingRoom.ts:1)
> 1
因此,它表明第二个集线器函数将在创建集线器实例之前执行,并且出现错误。
集线器函数返回JQueryPromise,因此我尝试让一个函数在集线器函数完成时返回一个Promise。 有人可以指出我的代码和试用版中的错误吗?
我认为问题在于HubStart
和HubUserOnline
不会返回诺言,相反,您陷入了诺言反模式。
请尝试以下操作:
//Hub functions
//Initializing hub server and clients.
function HubStart() {
return new Promise((resolve, reject) => {
$.connection.hub.start().then(() => {
console.log(1);
resolve();
});
});
}
//Hub server-side function that add user's name to chat board.
function HubUserOnline(user: any) {
return new Promise((resolve, reject) => {
$.connection.boardHub.server.userOnline(user).then(() => {
resolve();
});
});
}
//Main
var viewModel = ko.mapping.fromJS(model, mappingOption);
main();
//Definition of the main function
async function main() {
console.log(0);
await HubStart();
console.log(2);
await HubUserOnline(ko.mapping.toJS(viewModel.CurrentUser))
console.log(3);
}
});
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