Error: Stream.pipe is not a function

I tried to follow along with the example provided but when i run this code i get an error, stream.pipe is not a function. Im new to pg and nodeJS so Im not exactly sure where/how to fix this issue. This is the code i’ve been trying to run. Side note: Will running pg-query-stream allow me to use the results from the query in other js functions? Thanks, any help/advice is much appreciated.

const {Pool} = require('pg')

const QueryStream = require('pg-query-stream')
const JSONStream = require('JSONStream')

const pool = new Pool({})


const q = 'SELECT * FROM public."HexLogRecord"'

pool.connect()

var stream = pool.query(new QueryStream(q))

stream.pipe(JSONStream.stringify()).pipe(process.stdout)

[villesau]

Is there a reason why pool.query couldn’t handle the query stream case? I tinkered a bit and found my self basically marrying query stream and connection handling in a way that I think should be handled by the library under the hood, but now in the user space instead.

Now it would look something like this which easily makes the code pretty cluttered and rigid:

  const client = await pool.connect();
  const queryStream = client
    .query(new QueryStream('SELECT * FROM sometable'))
    .pipe(parser);
  queryStream.on('data', handleData);
  queryStream.on('end', () => {
    client.release();
  });
  queryStream.on('error', () => {
    client.release();
  });

while it could as well look like this:

  const queryStream = await pool
    .query(new QueryStream('SELECT * FROM sometable'))
    .pipe(parser);
  queryStream.on('data', handleData);

try{} finally{} does not work with query streams since stream might be still running after the promise will finish.

[sehrope]

You can use the pool but you need to check out the connection as the pool thinks the entire command is complete when the original query function returns. So use client = await pool.connect() and then release the connection after you finish streaming the results.