swr/esm/cache.js

import { mutate } from './use-swr';
import hash from './libs/hash';
export default class Cache {
    constructor(initialData = {}) {
        this.__cache = new Map(Object.entries(initialData));
        this.__listeners = [];
    }
    get(key) {
        const [_key] = this.serializeKey(key);
        return this.__cache.get(_key);
    }
    set(key, value, shouldNotify = true) {
        const [_key] = this.serializeKey(key);
        this.__cache.set(_key, value);
        if (shouldNotify)
            mutate(key, value, false);
        this.notify();
    }
    keys() {
        return Array.from(this.__cache.keys());
    }
    has(key) {
        const [_key] = this.serializeKey(key);
        return this.__cache.has(_key);
    }
    clear(shouldNotify = true) {
        if (shouldNotify)
            this.__cache.forEach(key => mutate(key, null, false));
        this.__cache.clear();
        this.notify();
    }
    delete(key, shouldNotify = true) {
        const [_key] = this.serializeKey(key);
        if (shouldNotify)
            mutate(key, null, false);
        this.__cache.delete(_key);
        this.notify();
    }
    // TODO: introduce namespace for the cache
    serializeKey(key) {
        let args = null;
        if (typeof key === 'function') {
            try {
                key = key();
            }
            catch (err) {
                // dependencies not ready
                key = '';
            }
        }
        if (Array.isArray(key)) {
            // args array
            args = key;
            key = hash(key);
        }
        else {
            // convert null to ''
            key = String(key || '');
        }
        const errorKey = key ? 'err@' + key : '';
        return [key, args, errorKey];
    }
    subscribe(listener) {
        if (typeof listener !== 'function') {
            throw new Error('Expected the listener to be a function.');
        }
        let isSubscribed = true;
        this.__listeners.push(listener);
        return () => {
            if (!isSubscribed)
                return;
            isSubscribed = false;
            const index = this.__listeners.indexOf(listener);
            if (index > -1) {
                this.__listeners[index] = this.__listeners[this.__listeners.length - 1];
                this.__listeners.length--;
            }
        };
    }
    // Notify Cache subscribers about a change in the cache
    notify() {
        for (let listener of this.__listeners) {
            listener();
        }
    }
}