react-cache-promise/dist/es/index.js

react-cache-promise

import * as React from 'react';

const promiseCache = new Map();
const reverseCache = new Map();
function createCache(arg, promise) {
    let subscriptionCache = {
        subscribe,
        state: null,
        active: true,
    };
    promise.then(fulfilledValue => {
        if (subscriptionCache.active) {
            subscriptionCache.state = { status: "fulfilled", value: fulfilledValue };
            if (subscriptionCache.listeners) {
                Object.values(subscriptionCache.listeners).forEach(cb => {
                    React.startTransition(() => cb(fulfilledValue));
                });
            }
        }
    }, (error) => {
        if (subscriptionCache.active) {
            subscriptionCache.state = { status: "rejected", reason: error };
            if (subscriptionCache.listeners) {
                Object.values(subscriptionCache.listeners).forEach(cb => {
                    React.startTransition(() => cb(error));
                });
            }
        }
    });
    function subscribe(cb) {
        if (!subscriptionCache.index) {
            subscriptionCache.index = 0;
        }
        if (!subscriptionCache.listeners) {
            subscriptionCache.listeners = [];
        }
        let id = ++subscriptionCache.index;
        subscriptionCache.listeners[id] = cb;
        return () => {
            delete subscriptionCache.listeners[id];
        };
    }
    return subscriptionCache;
}
function patchQuery(fn, getCacheArg) {
    function modified(...args) {
        let arg = getCacheArg.apply(null, args);
        let cachedPromise = promiseCache.get(arg);
        if (cachedPromise) {
            return cachedPromise;
        }
        let promise = fn.apply(null, args);
        promiseCache.set(arg, promise);
        reverseCache.set(promise, createCache(arg, promise));
        return promise;
    }
    return modified;
}
function usePromise(promise) {
    let subscription = reverseCache.get(promise);
    let state = subscription.state;
    if (state === null) {
        throw promise;
    }
    if (state.status === "rejected") {
        throw state.reason;
    }
    let rerender = React.useState()[1];
    React.useEffect(() => subscription.subscribe(rerender), [subscription]);
    return state.value;
}
function evict(arg) {
    let promise = promiseCache.get(arg);
    if (!promise) {
        return;
    }
    let subscription = reverseCache.get(promise);
    if (!subscription) {
        return;
    }
    let returnValue = promiseCache.delete(arg) && reverseCache.delete(promise);
    subscription.active = false;
    subscription.state = null;
    let listeners = subscription.listeners;
    if (listeners) {
        let newObject = {};
        Object.values(listeners).forEach(cb => {
            React.startTransition(() => cb(newObject));
        });
    }
    return returnValue;
}

export { evict, patchQuery, usePromise };
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