多个订阅导致源流两次发射
我想使用rxjs收听点击，执行事务并跟踪事务状态：
function performTransaction() {
const status = {
'0': 'pending',
'1': 'success'
}
return interval(1000).pipe(take(2), map((i) => status[`${i}`]))
}
const click$ = new Subject<void>()
const claimTxnState$ = click$.pipe(switchMap(() => {
console.log('performing transaction') // -> runs once which is expected
return performTransaction()
}))
claimTxnState$.subscribe((v) => {
console.log('claimTxnState', v);
})
export default function App() {
return (
<div className="App">
<button onClick={() => click$.next()}>click me</button>
</div>
);
}
这会导致执行事务要输出一次，这是预期的。
但是我想将sipertxnstate $传输到更多位置：
const claimIsPending$ = claimTxnState$.pipe(map((claim) => claim === 'pending'))
claimIsPending$.subscribe((v) => {
console.log('claimIsPending', v);
})
现在导致执行事务要输出两次，我理解这是因为这些是在每种订阅上重新创建的冷可观察物。但是我不想要这个。我只希望我的perstransaction被调用一次。我该如何实现？
I want to use RxJS to listen to clicks, perform a transaction, and keep track of the transaction status:
function performTransaction() {
const status = {
'0': 'pending',
'1': 'success'
}
return interval(1000).pipe(take(2), map((i) => status[`${i}`]))
}
const click$ = new Subject<void>()
const claimTxnState$ = click$.pipe(switchMap(() => {
console.log('performing transaction') // -> runs once which is expected
return performTransaction()
}))
claimTxnState$.subscribe((v) => {
console.log('claimTxnState', v);
})
export default function App() {
return (
<div className="App">
<button onClick={() => click$.next()}>click me</button>
</div>
);
}
This causes performing transaction to be output once, as is expected.
But I want to pipe claimTxnState$ to more places:
const claimIsPending$ = claimTxnState$.pipe(map((claim) => claim === 'pending'))
claimIsPending$.subscribe((v) => {
console.log('claimIsPending', v);
})
This now causes performing transaction to be output twice, which I understand because these are cold observables that get recreated on each subscription. But I don't want this. I only want my performTransaction to get called once. How can I achieve this?
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当我输入问题时，我找到了答案。我需要使用
共享操作员将可观察到的可观察到的可观察到cold转换为热>热。这具有共享sipertxnstate $之间的效果（即.pipes（...））：sandbox。
/Autumn-framework-piyymy?file=/src/app.tsx“ rel = ” “ nofollow noreferrer”>更多细节。
I found the answer as I was typing the question. I need to use the
shareoperator to convert the observable fromcoldtohot. This has the effect of sharingclaimTxnState$between all subscribers (i.e..pipes(...)):Sandbox.
More detail.