我有一个在节点上运行的打字稿应用程序。
我使用'EventEmitter'类来发出变量值的变化。
这是我的一段代码,
import events from 'events';
public async updateStream(streamContext: string, state: boolean): Promise<string> {
const eventEmitter = new events.EventEmitter();
if (state === true) {
return StreamManagement.instance.activeStreams.get(streamContext).streamState = 'Paused';
} else {
const streamState = StreamManagement.instance.activeStreams.get(streamContext).streamState = 'Active';
eventEmitter.emit('resume');
return streamState;
}
}
public async waitForStreamActive(stream: Stream) {
const eventEmitter = new events.EventEmitter();
// tslint:disable-next-line:no-unused-expression
return new Promise(( resolve ) => {
eventEmitter.on('resume', resolve );
});
}
这段代码很好。但是当我运行代码时,就像执行操作一样,我收到以下错误,
error: errorHandler - Apply - Hit Unhandled exception {"timestamp":"2019-04-29T12:33:49.209Z"}
error: errorHandler - Apply - Cannot read property 'EventEmitter' of undefined - TypeError: Cannot read property 'EventEmitter' of undefined
at StreamResource.updateStream (C:\Vertigo\core\reference_platform\dist\index.js:10695:51)
at StreamService.patchStream (C:\Vertigo\core\reference_platform\dist\index.js:22524:40)
at process._tickCallback (internal/process/next_tick.js:68:7) {"timestamp":"2019-04-29T12:33:49.215Z"}
我究竟做错了什么?
我已经设置了最小的项目来重现它,并立即编译器警告我:
TS1192: Module '"events"' has no default export.
但这似乎有效:
import * as EventEmitter from 'events'
new EventEmitter();