get fields at the start of the stream

[gajus]

This is how I currently consume the stream:

const query = new QueryStream('SELECT * FROM foo');

const queryStream = connect.query(query);

queryStream.on('data', (row) => {
  console.log(row);
});

However, is there a way to get the field description at the beginning of the stream?

Something similar to what pg provides for query results, i.e.

type FieldType = {|
  +columnID: number,
  +dataTypeID: number,
  +dataTypeModifier: number,
  +dataTypeSize: number,
  +format: string,
  +name: string,
  +tableID: number
|};

[gajus]

Having looked at the source code, pg-query-stream is a wrapper around pg-cursor. Meanwhile, pg-cursor does have access to result object.

It could be implemented simply as:

_read (size) {
  if (this._reading || this._closed) {
    return false
  }
  this._reading = true
  const readAmount = Math.max(size, this.batchSize)
-    this.cursor.read(readAmount, (err, rows) => {
+    this.cursor.read(readAmount, (err, rows, result) => {
    if (this._closed) {
      return
    }
    if (err) {
      return this.emit('error', err)
    }
    // if we get a 0 length array we've read to the end of the cursor
    if (!rows.length) {
      this._closed = true
      setImmediate(() => this.emit('close'))
      return this.push(null)
    }

    // push each row into the stream
    this._reading = false
    for (var i = 0; i < rows.length; i++) {
-        this.push(rows[i])
+        this.push({row: rows[i], fields: result.fields})
    }
  })
}

[gajus]

As a quick workaround, I have inlined pg-query-stream.

This is the solution that I have used:

gajus/slonik@fce4d22

As suggested in this issue, each date event emits row and fields data.