How to get response after Loop of requests finished

Question

I try to do multiple requests in for each loop and push data response to an array but I get always the first item only

//Get all roles
router.get('/', async (req, res) =>{

    try {

        knex.from( roles_table )
        .then(roles => {
            let rolePermissions =[];
            roles.forEach(role => {
                knex.select(permissions_table + '.*').from(permissions_table)
                    .innerJoin(permissions_roles_table, permissions_table + '.id', permissions_roles_table +'.id_permission')
                    .where(permissions_roles_table + '.id_role', '=', role.id)
                .then(rows => {
                    role.permissions = rows;
                    rolePermissions.push(role)
                });
                
            });
            
            res.status(200).json(rolePermissions);
            

           
        });
       
    } catch (err) {
        res.status(500).json({message: err});
    }
});

Does this answer your question? [How to return many Promises and wait for them all before doing other stuff](https://stackoverflow.com/questions/31426740/how-to-return-many-promises-and-wait-for-them-all-before-doing-other-stuff) — Ryan Wilson, Oct 27 '20 at 15:06

score 1 · Answer 1 · answered Oct 27 '20 at 15:19

1

You must learn about Promise and asynchrone if you want to do modern JS.

Something like that could be what you are looking for

//This const will store an array of Promise
const allRows = knex.from( roles_table )
.then(roles => {
    return roles.map(role => {
        return knex.select(permissions_table + '.*').[...]
    });
});

//This method will wait for each promises to succeed or first one to failed
return Promise.all(allRows)
.then( allRows => {
    //allRows is now an array containing all the results
    res.status(200).json(rolePermissions);
})
.catch (err) {
    res.status(500).json({message: err});
});

By the way, you don't need try/catch a Promise, there is the .catch method

answered Oct 27 '20 at 15:19

farvilain

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thank you , but it's ,not work because the problem is in inside of loop ,i do multiple requests – Boutamente abdessamad Oct 27 '20 at 15:58
Yeah, multiple requests inside a loop... that's the solution I gaved you. – farvilain Oct 27 '20 at 16:03
`return knex.select(permissions_table + '.*').[...]` this part what should return ? – Boutamente abdessamad Oct 27 '20 at 16:05
Me i create array to to push items – Boutamente abdessamad Oct 27 '20 at 16:07

How to get response after Loop of requests finished

1 Answers1