How to destructure multiple query results in sequence?

Question

I want to use the same pattern for destructuring query results, but seems I cannot. In the following code:

var {rows} = await client.query("SELECT id FROM mytable;");
var Id = rows[0].id; //destructured here as expected

if I then follow that with:

rows = await client.query('SELECT max(id) as id FROM table2;');

The only way I can access the value is like this:

rows.rows[0].id;

Shouldn't I be able to access as in the first instance, like this?

rows[0].id;

Do I need to somehow reset {rows}?

Very new to JS so finding my way.

client.query returns you an object with a property 'rows.' Assigning the variable you've created by destructuring to the return value of client.query will result in rows.rows. — Devin Fields, Jul 24 '18 at 23:18

score 2 · Accepted Answer · answered Jul 25 '18 at 00:02

You still need to restructure the variable. Simply assign to rows will just get the full response object assigned to the variable, as you've seen.

Destructuring to the same variable has a couple gotchas because you can't do this:

let {rows} = await client.query("SELECT id FROM mytable;");
// Error: unexpected token without declaration
{rows} = await client.query('SELECT max(id) as id FROM table2;');
// Error: Identifier 'rows' has already been declared
let {rows} = await client.query('SELECT max(id) as id FROM table2;');

You can declare var multiple times:

var {rows} = await client.query("SELECT id FROM mytable;");
// no problemo
var {rows} = await client.query('SELECT max(id) as id FROM table2;');

If you want to declare with let then you need to do something like:

let {rows} = await client.query("SELECT id FROM mytable;");
// this works too…
({rows} = await client.query('SELECT max(id) as id FROM table2;'));

How to destructure multiple query results in sequence?

1 Answers1