这就是我所拥有的：
ngOnInit() {
this._addServ.getDefaultAddress().subscribe((res)=>{
if(res.status){
//I need these next two functions to finish their async API requests
//before selectNormalDelivery is called
this.selectShippingAddress();
this.selectBillingAddress();
this.selectNormalDelivery();
}
})
}
我需要selectShippingAddress和selectBillingAddress完成他们的电话，然后selectNormalDelivery被调用。我怎样才能做到这一点？我不想将它们转换为承诺，因为它们在其他时候不需要被链接。这是否涉及.then？
这是函数的代码：
selectShippingAddress(){
this.addressService.setShippingAddresses(this.cartService.shippingAddress.address_id).subscribe((res) => {
console.log('Set shipping address!')
console.log(res);
}, err => {
console.log('Failed to set shipping address')
console.log(err);
})
}
selectBillingAddress(){
this.addressService.setPaymentAddresses(this.cartService.billingAddress.address_id).subscribe((res) => {
console.log('Set billing address!')
console.log(res);
}, err => {
console.log('Failed to set billing address')
console.log(err);
})
}
如果我尝试 a .then，我会收到错误Property 'then' does not exist on type 'void'.，这是有道理的，因为我不想返回任何东西，我只需要他们为了 API 完成调用。
建议？
如果我理解正确，您需要听一个 observable (from getDefaultAddress())，然后处理另外两个 observables ( this.addressService.setShippingAddresses()and this.addressService.setPaymentAddresses())，然后调用 function selectNormalDelivery()。
您可以通过使用 RxJS switchMap、catchError、tap运算符和forkJoin(). 尝试以下
import { forkJoin, EMPTY } from 'rxjs';
import { tap, catchError, switchMap } from 'rxjs/operators';
ngOnInit() {
this._addServ.getDefaultAddress().pipe(
switchMap((res) => { // <-- map the observable from `getDefaultAddress()` to another observable
if(res.status) {
return forkJoin([ // <-- `forkJoin` emits only after the observables complete
this.selectShippingAddress(), this.selectBillingAddress()
])
}
})
).subscribe(response => {
this.selectNormalDelivery()
})
}
selectShippingAddress() {
return this.addressService.setShippingAddresses(this.cartService.shippingAddress.address_id).pipe(
tap((res) => { // <-- `tap` doesn't alter the response
console.log('Set shipping address!')
console.log(res);
}),
catchError((err) => { // <-- `catchError` must return an observable
console.log('Failed to set shipping address')
console.log(err);
return EMPTY;
}))
}
selectShippingAddress() {
return this.addressService.setPaymentAddresses(this.cartService.shippingAddress.address_id).pipe(
tap((res) => {
console.log('Set billing address!')
console.log(res);
}),
catchError((err) => {
console.log('Failed to set billing address')
console.log(err);
return EMPTY;
}))
}
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我来说两句