Co-pg NPM | npm.io

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());
	}
});