datastore-core/dist/src/namespace.js

Wrapper implementation for interface-datastore

import { Key } from 'interface-datastore';
import map from 'it-map';
import { KeyTransformDatastore } from './keytransform.js';
/**
 * Wraps a given datastore into a keytransform which
 * makes a given prefix transparent.
 *
 * For example, if the prefix is `new Key(/hello)` a call
 * to `store.put(new Key('/world'), mydata)` would store the data under
 * `/hello/world`.
 */
export class NamespaceDatastore extends KeyTransformDatastore {
    iChild;
    iKey;
    constructor(child, prefix) {
        super(child, {
            convert(key) {
                return prefix.child(key);
            },
            invert(key) {
                if (prefix.toString() === '/') {
                    return key;
                }
                if (!prefix.isAncestorOf(key)) {
                    throw new Error(`Expected prefix: (${prefix.toString()}) in key: ${key.toString()}`);
                }
                return new Key(key.toString().slice(prefix.toString().length), false);
            }
        });
        this.iChild = child;
        this.iKey = prefix;
    }
    query(q, options) {
        const query = {
            ...q
        };
        query.filters = (query.filters ?? []).map(filter => {
            return ({ key, value }) => filter({ key: this.transform.invert(key), value });
        });
        const { prefix } = q;
        if (prefix != null && prefix !== '/') {
            delete query.prefix;
            query.filters.push(({ key }) => {
                return this.transform.invert(key).toString().startsWith(prefix);
            });
        }
        if (query.orders != null) {
            query.orders = query.orders.map(order => {
                return (a, b) => order({ key: this.transform.invert(a.key), value: a.value }, { key: this.transform.invert(b.key), value: b.value });
            });
        }
        query.filters.unshift(({ key }) => this.iKey.isAncestorOf(key));
        return map(this.iChild.query(query, options), ({ key, value }) => {
            return {
                key: this.transform.invert(key),
                value
            };
        });
    }
    queryKeys(q, options) {
        const query = {
            ...q
        };
        query.filters = (query.filters ?? []).map(filter => {
            return (key) => filter(this.transform.invert(key));
        });
        const { prefix } = q;
        if (prefix != null && prefix !== '/') {
            delete query.prefix;
            query.filters.push((key) => {
                return this.transform.invert(key).toString().startsWith(prefix);
            });
        }
        if (query.orders != null) {
            query.orders = query.orders.map(order => {
                return (a, b) => order(this.transform.invert(a), this.transform.invert(b));
            });
        }
        query.filters.unshift(key => this.iKey.isAncestorOf(key));
        return map(this.iChild.queryKeys(query, options), key => {
            return this.transform.invert(key);
        });
    }
}
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