How to configure types only for a particular instance of node-postgres?

[gajus]

It appears that the only way to configure type parser is by doing so globally, i.e.

var types = require('pg').types
types.setTypeParser(20, function(val) {
  return parseInt(val)
});

– https://github.com/brianc/node-pg-types

I would like to restrict type parsing to a particular connection.

Is there an API at the moment to do so?

[gajus]

This could be as simple as allowing to override types.

node-postgres/lib/index.js

Line 34 in fcd0f02

this.types = require('pg-types')

[charmander]

pg.types is a convenience reexport; pg itself doesn’t use that property. You can override type parsing by configuration (i.e. per client or pool) by passing something that satisfies the necessary interface in the types property, the most convenient something I’m aware of being a TypeOverrides from pg/lib/type-overrides.js:

const TypeOverrides = require('pg/lib/type-overrides');

const OID_INT8 = 20;

const types = new TypeOverrides();
types.setTypeParser(OID_INT8, BigInt);

const pool = new pg.Pool({
    ⋮
    types,
});

const client = new pg.Client({
    ⋮
    types,
});

[gajus]

Is there a way to override TypeOverrides after pool has been instantiated?

const client = new pg.Client({});

client._types = types;

The latter does not seem to do the trick.

Will debug this further on my own (seems like I could definitely override the query getTypeParser,

node-postgres/lib/client.js

Line 459 in fcd0f02

query._result._getTypeParser = this._types.getTypeParser.bind(this._types)

), but if there is a better way, please let me know.

[charmander]

Is there a way to override TypeOverrides after pool has been instantiated? … new pg.Client

On a pool or a client? What you wrote should work fine for a client for queries after the assignment. Client.prototype.setTypeParser/Client.prototype.getTypeParser exist too. On a pool, you can assign arbitrary client options after instantiation, so set pool.options.types.

[gajus]

Thank you

[gajus]

Just in case anyone comes across this, if you are using pg-native, you also need to override client.native._types. See gajus/slonik@009a212.