等待函数完成并返回Angular 6

function waitFunction(): Promise<any> {
  return new Promise((resolve, reject) => {
    // 异步操作
    setTimeout(() => {
      resolve('函数已完成');
    }, 2000);
  });
}

waitFunction().then(result => {
  console.log(result); // 输出：函数已完成
});

import { Observable } from 'rxjs';

function waitFunction(): Observable<any> {
  return new Observable(observer => {
    // 异步操作
    setTimeout(() => {
      observer.next('函数已完成');
      observer.complete();
    }, 2000);
  });
}

waitFunction().subscribe(result => {
  console.log(result); // 输出：函数已完成
});

async function waitFunction(): Promise<any> {
  return new Promise((resolve, reject) => {
    // 异步操作
    setTimeout(() => {
      resolve('函数已完成');
    }, 2000);
  });
}

async function main() {
  const result = await waitFunction();
  console.log(result); // 输出：函数已完成
}

main();