Inheriting pg.Pool will overwrite any custom methods.

[ghost]

If you were to create a class that inherits pg.Pool like so:

const pg = require('pg');

class Db extends pg.Pool {
  insert(args) {
    return this.query('...');
  }
}

const a = new Db();

console.log(a.insert); // undefined

The method insert() would be undefined on all instances of this custom class. If you were to do the exact same thing with pg.Client, it works as expected.

[charmander]

pg doesn’t quite export the Pool type. Since Pool is an ES6 class, though, there’s no nice way to let BoundPool inherit from it instead while maintaining backwards compatibility (allowing pg.Pool() to be called without new).

You can access pg-pool directly instead (making sure to add a dependency on it in your package.json):

const {Client} = require('pg');
const Pool = require('pg-pool');

class Db extends Pool {
  constructor(options) {
    super({Client, ...options});
  }
  ⋮

@brianc, any interest in deprecating calling BoundPool without new?