expo-sqlite/src/WebStorage.ts

Provides access to a database using SQLite (https://www.sqlite.org/). The database is persisted across restarts of your app.

import { installGlobal as install } from 'expo/internal/install-global';

import { Storage as KVStorage, type SQLiteStorage } from './Storage';

class Storage {
  constructor(private readonly storage: SQLiteStorage) {}

  clear(): void {
    this.storage.clearSync();
  }

  getItem(key: string): string | null {
    return this.storage.getItemSync(key);
  }

  key(index: number): string | null {
    return this.storage.getKeyByIndexSync(index);
  }

  removeItem(key: string): void {
    this.storage.removeItemSync(key);
  }

  setItem(key: string, value: string): void {
    this.storage.setItemSync(key, String(value));
  }

  get length(): number {
    return this.storage.getLengthSync();
  }

  toString(): string {
    return '[object Storage]';
  }
}

/**
 * A Proxy wrapper that allows property accessors to be used on the `WebStorageWrapper` object.
 */
function withPropertyAccessors(obj: Storage): Storage & Record<string, string | undefined> {
  if (typeof Proxy !== 'function') {
    return obj as Storage & Record<string, string | undefined>;
  }

  const builtin = new Set();
  let proto = obj;
  while (proto) {
    Object.getOwnPropertyNames(proto).forEach((name) => builtin.add(name));
    proto = Object.getPrototypeOf(proto);
  }

  return new Proxy(obj as Storage & Record<string, string | undefined>, {
    get(target, prop, receiver) {
      if (typeof prop !== 'string' || builtin.has(prop)) {
        return Reflect.get(target, prop, receiver);
      }
      // Values are always converted to strings so getItem returns null only when there is no value
      const value = target.getItem(prop);
      return value === null ? undefined : value;
    },
    set(target, prop, value, receiver) {
      if (typeof prop !== 'string' || builtin.has(prop)) {
        return Reflect.set(target, prop, value, receiver);
      }
      target.setItem(prop, String(value));
      return true;
    },
    deleteProperty(target, prop) {
      if (typeof prop !== 'string' || Reflect.ownKeys(target).includes(prop)) {
        return Reflect.deleteProperty(target, prop);
      }
      target.removeItem(prop);
      return true;
    },
    has(target, prop) {
      if (typeof prop !== 'string' || builtin.has(prop)) {
        return Reflect.has(target, prop);
      }
      return target.getItem(prop) !== null;
    },
  });
}

/**
 * The default instance of the [`SQLiteStorage`](#sqlitestorage-1) class is used as a drop-in implementation for the [`localStorage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage) object from the Web.
 */
export const localStorage = withPropertyAccessors(new Storage(KVStorage));

/**
 * Install the `localStorage` on the `globalThis` object.
 */
export function installGlobal() {
  install('localStorage', () => localStorage);
}