shelving/db/ItemStore.js

Toolkit for using data in JavaScript.

import { RequiredError } from "../error/RequiredError.js";
import { BooleanStore } from "../store/BooleanStore.js";
import { OptionalDataStore } from "../store/DataStore.js";
import { getGetter } from "../util/class.js";
import { NONE } from "../util/constants.js";
import { getItem } from "../util/item.js";
import { runSequence } from "../util/sequence.js";
/** Store a single item. */
export class ItemStore extends OptionalDataStore {
    provider;
    collection;
    id;
    busy = new BooleanStore();
    /** Get the data of this store (throws `RequiredError` if item doesn't exist). */
    get data() {
        const item = this.value;
        if (!item)
            throw new RequiredError(`Item does not exist in collection "${this.collection}"`, {
                store: this,
                provider: this.provider,
                collection: this.collection,
                id: this.id,
                caller: getGetter(this, "data"),
            });
        return item;
    }
    /** Set the data of this store. */
    set data(data) {
        this.value = getItem(this.id, data);
    }
    constructor(collection, id, provider, memory) {
        const time = memory?.getItemTime(collection, id);
        const item = memory?.getItem(collection, id);
        super(typeof time === "number" || item ? item : NONE, time); // Use the cached value if it was definitely cached or is not undefined.
        if (memory)
            this.starter = store => runSequence(store.through(memory.getCachedItemSequence(collection, id)));
        this.provider = provider;
        this.collection = collection;
        this.id = id;
        // Start loading the value from the provider if it wasn't cached.
        if (typeof time !== "number")
            this.refresh();
    }
    /** Refresh this store from the source provider. */
    refresh(provider = this.provider) {
        if (!this.busy.value)
            void this._refresh(provider);
    }
    async _refresh(provider) {
        this.busy.value = true;
        this.reason = undefined; // Optimistically clear the error.
        try {
            this.value = await provider.getItem(this.collection, this.id);
        }
        catch (thrown) {
            this.reason = thrown;
        }
        finally {
            this.busy.value = false;
        }
    }
    /** Refresh this store if data in the cache is older than `maxAge` (in milliseconds). */
    refreshStale(maxAge, provider) {
        if (this.age > maxAge)
            this.refresh(provider);
    }
    /** Subscribe this store to a provider. */
    connect(provider = this.provider) {
        return runSequence(this.through(provider.getItemSequence(this.collection, this.id)));
    }
}