packages/react-hooks/src/useCallMulti.ts
// Copyright 2017-2024 @polkadot/react-hooks authors & contributors
// SPDX-License-Identifier: Apache-2.0
import type { ApiPromise } from '@polkadot/api';
import type { QueryableStorageMultiArg } from '@polkadot/api/types';
import type { Tracker } from './useCall.js';
import type { MountedRef } from './useIsMountedRef.js';
import { useEffect, useRef, useState } from 'react';
import { isUndefined, nextTick } from '@polkadot/util';
import { useApi } from './useApi.js';
import { handleError, transformIdentity, unsubscribe } from './useCall.js';
import { useIsMountedRef } from './useIsMountedRef.js';
interface TrackerRef {
current: Tracker;
}
interface CallOptions <T> {
defaultValue?: T;
transform?: (value: any, api: ApiPromise) => T;
}
// subscribe, trying to play nice with the browser threads
function subscribe <T> (api: ApiPromise, mountedRef: MountedRef, tracker: TrackerRef, calls: QueryableStorageMultiArg<'promise'>[], setValue: (value: T) => void, { transform = transformIdentity }: CallOptions<T> = {}): void {
unsubscribe(tracker);
nextTick((): void => {
if (mountedRef.current) {
const included = calls.map((c) => !!c && (!Array.isArray(c) || !!c[0]));
const filtered = calls.filter((_, index) => included[index]);
if (filtered.length) {
// swap to active mode
tracker.current.isActive = true;
tracker.current.subscriber = api.queryMulti(filtered, (value): void => {
// we use the isActive flag here since .subscriber may not be set on immediate callback)
if (mountedRef.current && tracker.current.isActive) {
let valueIndex = -1;
try {
setValue(
transform(
calls.map((_, index) =>
included[index]
? value[++valueIndex]
: undefined
),
api
)
);
} catch (error) {
handleError(error as Error, tracker);
}
}
}).catch((error) => handleError(error as Error, tracker));
} else {
tracker.current.subscriber = null;
}
}
});
}
// very much copied from useCall
// FIXME This is generic, we cannot really use createNamedHook
export function useCallMulti <T> (calls?: QueryableStorageMultiArg<'promise'>[] | null | false, options?: CallOptions<T>): T {
const { api } = useApi();
const mountedRef = useIsMountedRef();
const tracker = useRef<Tracker>({ error: null, fn: null, isActive: false, serialized: null, subscriber: null, type: 'useCallMulti' });
const [value, setValue] = useState<T>(() => (isUndefined(options?.defaultValue) ? [] : options?.defaultValue) as unknown as T);
// initial effect, we need an un-subscription
useEffect((): () => void => {
return () => unsubscribe(tracker);
}, []);
// on changes, re-subscribe
useEffect((): void => {
// check if we have a function & that we are mounted
if (mountedRef.current && calls) {
const serialized = JSON.stringify(calls);
if (serialized !== tracker.current.serialized) {
tracker.current.serialized = serialized;
subscribe(api, mountedRef, tracker, calls, setValue, options);
}
}
}, [api, calls, options, mountedRef]);
// throwOnError(tracker.current);
return value;
}