co-pg

Co wrapper for node-postgres. Also supports ESNext's async/await.

Installation

$ npm install co-pg

Overview

co-pg provides higher order functions that will return a wrapped edition of pg. Everything that is available from pg is also available on co-pg with no alterations to the original API. The pg API methods that use a callback style interface also have companion promise methods that are usable by co 4.0 and by ESNext async/await.

Supports:

• node-postgres
• node-pg-native
• node-postgres-pure (even though it has been deprecated)

Supports Node Engines:

• v0.12 (requires --harmony flag to work)
• v4
• v5

API Additions

co-pg adds a few additional methods on top of the pg API.

• PG prototype adds the #connectAsync method
  • also includes #connectPromise which aliases #connectAsync
• Client prototype adds the #connectAsync and #queryAsync methods
  • also includes #connectPromise which aliases #connectAsync
  • also includes #queryPromise which aliases #queryAsync

These methods behave exactly the same as their counter-parts, including their arguments, except instead of supplying a callback, the promise is yielded. All the original methods are still available by using the sans-underscore methods. For documentation or help on how they work, please see the original project's documentation.

Examples

Single connection

Connect to a postgres instance, run a query, and disconnect, using co.

let co = require('co');
let pg = require('co-pg')(require('pg'));
 
let connectionString = 'postgres://postgres:1234@localhost/postgres';
 
co(function* connectExample() {
    try {
        let client = new pg.Client(connectionString);
        yield client.connectPromise();
 
        let result = yield client.queryPromise('select now() as "theTime"');
        console.log(result.rows[0].theTime);
 
        client.end();
    } catch (ex) {
        console.error(ex);
    }
});

Client pooling

The underlying pooling system is not altered. The companion thunk methods can be used instead. Since PG#Connect returns multiple objects, the return value is an array of those results. They can then be manually destructured into separate variables for cleaner code.

let co = require('co');
let pg = require('co-pg')(require('pg'));
 
let connectionString = 'postgres://postgres:1234@localhost/postgres';
 
co(function* poolExample() {
    try {
        let connectResults = yield pg.connectPromise(connectionString);
        let client = connectResults[0];
        let done = connectResults[1];
 
        let result = yield client.queryPromise('select now() as "theTime"');
        //call `done()` to release the client back to the pool
        done();
 
        console.log(result.rows[0].theTime);
        process.exit();
    } catch (ex) {
        console.error(ex.toString());
    }
});

Other projects

• brianc/node-postgres: the PostgreSQL driver
• brianc/node-pg-native: the PostgreSQL drive using native bindings

License

MIT