`createPostgresPersister`

The createPostgresPersister function creates a PostgresPersister object that can persist the Store to a local PostgreSQL database.

createPostgresPersister(
  store: Store | MergeableStore,
  sql: Sql<{}>,
  configOrStoreTableName?: string | DatabasePersisterConfig,
  onSqlCommand?: (sql: string, params?: any[]) => void,
  onIgnoredError?: (error: any) => void,
): Promise<PostgresPersister>

	Type	Description
`store`	`Store \| MergeableStore`	The `Store` or `MergeableStore` to persist.
`sql`	`Sql<{}>`	The database connection that was returned from `postgres(...)`.
`configOrStoreTableName?`	`string \| DatabasePersisterConfig`	A `DatabasePersisterConfig` to configure the persistence mode (or a string to set the `storeTableName` property of the JSON serialization).
`onSqlCommand?`	`(sql: string, params?: any[]) => void`	An optional handler called every time the `Persister` executes a SQL command or query. This is suitable for logging persistence behavior in a development environment.
`onIgnoredError?`	`(error: any) => void`	An optional handler for the errors that the `Persister` would otherwise ignore when trying to save or load data. This is suitable for debugging persistence issues in a development environment.
returns	`Promise<PostgresPersister>`	A reference to the new `PostgresPersister` object.

A PostgresPersister supports regular Store objects, and can also be used to persist the metadata of a MergeableStore when using the JSON serialization mode, as described below.

As well as providing a reference to the Store to persist, you must provide a sql parameter which identifies the database connection.

A database Persister uses one of two modes: either a JSON serialization of the whole Store stored in a single row of a table (the default), or a tabular mapping of Table Ids to database table names and vice-versa).

The third argument is a DatabasePersisterConfig object that configures which of those modes to use, and settings for each. If the third argument is simply a string, it is used as the storeTableName property of the JSON serialization.

See the documentation for the DpcJson and DpcTabular types for more information on how both of those modes can be configured.

This method is asynchronous because it will await the creation of dedicated new connections to the database. You will need to await a call to this function or handle the return type natively as a Promise.

Examples

This example creates a PostgresPersister object and persists the Store to a local PostgreSQL database as a JSON serialization into the my_tinybase table. It makes a change to the database directly and then reloads it back into the Store.

import {createPostgresPersister} from 'tinybase/persisters/persister-postgres';
import {createStore} from 'tinybase';
import postgres from 'postgres';

const sql = postgres('postgres://localhost:5432/tinybase');
const store = createStore().setTables({pets: {fido: {species: 'dog'}}});
const persister = await createPostgresPersister(store, sql, 'my_tinybase');

await persister.save();
// Store will be saved to the database.

console.log(await sql`SELECT * FROM my_tinybase;`);
// -> [{_id: '_', store: '[{"pets":{"fido":{"species":"dog"}}},{}]'}]

const json = '[{"pets":{"felix":{"species":"cat"}}},{}]';
await sql`UPDATE my_tinybase SET store = ${json} WHERE _id = '_';`;

await persister.load();
console.log(store.getTables());
// -> {pets: {felix: {species: 'cat'}}}

persister.destroy();
await sql.end();

This example creates a PostgresPersister object and persists the Store to a local PostgreSQL database with tabular mapping.

import {createPostgresPersister} from 'tinybase/persisters/persister-postgres';
import {createStore} from 'tinybase';
import postgres from 'postgres';

const sql = postgres('postgres://localhost:5432/tinybase');
const store = createStore().setTables({pets: {fido: {species: 'dog'}}});
const persister = await createPostgresPersister(store, sql, {
  mode: 'tabular',
  tables: {load: {pets: 'pets'}, save: {pets: 'pets'}},
});

await persister.save();
console.log(await sql`SELECT * FROM pets;`);
// -> [{_id: 'fido', species: '"dog"'}]
// Note that Cells and Values are JSON-encoded in PostgreSQL databases.

await sql`INSERT INTO pets (_id, species) VALUES ('felix', '"cat"')`;
await persister.load();
console.log(store.getTables());
// -> {pets: {fido: {species: 'dog'}, felix: {species: 'cat'}}}

persister.destroy();
await sql`DROP TABLE IF EXISTS pets`;
await sql.end();

Since

5.2.0