How to use async/await to get data from sqlite db.each

Question

I would like to get my data out from the sqlite db.each function using the promise object and the async/await I tried to do it but I don't really understand how to do it and I would like some explanations

my code below :

var sqlite3 = require('sqlite3').verbose();
var db = new sqlite3.Database('./data.sqlite', (err) => {
    if (err) {
        console.error(err.message);
    }
    console.log('Connected to the database');
});

 function request (req) {
    new Promise(function (resolve, reject) {
        db.each(req, function (err, row) {
            if (err)
                reject(err);
            else
                data.push(row);
        }, function (err, n) {
            if (err) {
                reject(err);
            }
            else
                resolve(data);
        });
    });
}

data = await request("select * from user "); //I'm getting errors here 



db.close((err) => {
    if (err) {
        return console.error(err.message);
    }
    console.log('Close the database connection');
});

new Promise( -> return new Promise(

Keith
– Keith

2020-05-22 13:43:57 +00:00
Commented May 22, 2020 at 13:43 — Keith
– Keith, Commented May 22, 2020 at 13:43

Yousaf · Accepted Answer · 2020-05-22 13:50:19Z

2

await can only be used inside an async function. Create an async function, inside this function, await the promise returned by request function

async function makeRequest() {
    data = await request("select * from user ");
}

and you need to return the promise from request function so that it can be awaited

function request (req) {
    return new Promise(function (resolve, reject) {
        // code
    });
}

edited May 22, 2020 at 13:50

answered May 22, 2020 at 13:43

Yousaf

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7 Comments

Tsuna Over a year ago

Thank you it works . By the way could you say me how to extract the data out from the functions to put them in a global variable .

Yousaf Over a year ago

you could define data outside of the makeRequest function

Tsuna Over a year ago

I tried this but I'm getting undefined at console.log(data) even after define it globally

Yousaf Over a year ago

you will get undefined because data variable is initialized after an asynchronous request. Log data inside makeRequest function after the await statement

Tsuna Over a year ago

But the my goal is to log it how the async function that is what I want since the beginning .I fought that the using of async/await will permit me to do this simply but it is the same as when I used promise .Do you have a method to have it outside async function

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