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    pg-reactive
    TypeScript icon, indicating that this package has built-in type declarations

    1.0.3 • Public • Published

    pg-reactive

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    ReactiveX

    RxJS interface for PostgreSQL in node.js

    Installation

    npm install pg-reactive

    If you are using RxJS v5, install a previous version:

    npm install pg-reactive@^0.3.5

    Example

    import PgRx from 'pg-reactive';
    import { map } from "rxjs/operators";
    
    const db = new PgRx('postgres://postgres@$localhost/tester');
    
    db.query('SELECT id FROM user')
      .pipe(
        map((row) => row.id)
      )
      .subscribe((id) => {
        console.log('ID: ', id);
      });

    Documentation

    TypeScript

    pg-reactive is shipped with its type declaration file and it can be used in a TypeScript directly.

    How it works?

    Before using this library or reading its source code, you should know Reactive Programming & RxJS.

    pg-reactive wraps the low-level pg APIs and exposes a RxJS-compatible interface. The work of pg-reactive includes the following three aspects.

    Deferred Query

    Unlike Promise as the final state of an asynchronous action, Observable works as a data source of asynchronous actions. When providing a observable-based API, pg-reactive cools down the original pg functions by deferring their execution using Rx.Observable.defer().

    In this way, the data stream is controllable with subscribe() / unsubscribe() without worrying data leak. The data stream is generated using the row, error, end event of the query object of pg, which ensures the query result is emitted by rows.

    Transaction as an Observable

    The tx() function of pg-reactive accepts a callback function where the user is able to organization the data flow within a transaction, which may includes different database operations. The data flow behind this function is actually query('BEGIN') -> query('Your Command') -> query('COMMIT') and a query('ROLLBACK') will be executed in cause of any error.

    Note that unlike the query observable, the tx observable doesn't emit data until the query is completely done. Therefore, the tx observable guarantees to emit nothing if error happens.

    License

    MIT

    Install

    npm i pg-reactive

    DownloadsWeekly Downloads

    73

    Version

    1.0.3

    License

    MIT

    Unpacked Size

    15.4 kB

    Total Files

    10

    Last publish

    Collaborators

    • haoliang