确保 for 循环中的可观察对象在执行其他代码之前全部完成

我有一段代码，如下所示：

getPersons().subscribe(
    persons => {
        for (const person of persons) {
            getAddress(person.id).subscribe(
                address => {
                    person.address = address;
                }
            );
        }
        doSomethingWithAddresses();
     }
);

问题是 doSomethingWithAddresses 在所有 getAddress 可观察对象完成之前执行。在执行后续代码之前如何确保它们全部完成？

你应该使用 RxJSforkJoin在返回所有可观察值之前等待 for..of 循环完成。

以下是您应该对代码进行的更改：

getPersons().subscribe(
  persons => {
    const observablesList = [];
    for (const person of persons) {
      const getAddressObservable = getAddress(person.id);
      observablesList.push(getAddressObservable)
    }
    forkJoin(observablesList).subscribe(response => {
      // console.log(response) to check that there is a list of returned observables
      const result = persons.map((person, index) => {
        person['address'] = response[index]['address'];
        return person;
      })
      doSomethingWithAddresses();
    })
  }
);

或者，您可以尝试这样做来防止链接subscribe()

getPersons().pipe(
  mergeMap(persons => {
    const observablesList = [];
    for (const person of persons) {
      const getAddressObservable = getAddress(person.id);
      observablesList.push(getAddressObservable)
    }
    return observablesList;
  })
).subscribe(response => {
  // console.log(response) to check that there is a list of returned observables
  const result = persons.map((person, index) => {
    person['address'] = response[index]['address'];
    return person;
  })
  doSomethingWithAddresses();
})