async and await on MySQL call in node js

Question

all I\'m pretty new to node and I just learned about the async and await function offered in javascript. I\'m trying to implement this method in the code snippet attached be

Answer 1

You have no return statement in your displayDB function.

Normally this would cause a function to return undefined, but because you declared it async, it causes it to return a Promise that is immediately resolved.

If you want it to wait until the database query is complete, then you need to explicitly return a new Promise which you resolve when you are ready (i.e. after you have called connection.end()).

Answer 2

You need to return a promise from the async function displayDB if you want to use the await keyword in test, you need to learn how promises work first. Pseudo code :

var displayDB = () => {
    return new Promise((resolve,reject)=>{
        connection.query('SELECT * FROM products', (err, resp) => {
            if (err) {
                reject(err)
            } else {
                const table = [];
                resp.forEach((product) => {
                    obj = {
                    'Product ID': product.productID,
                    'Category': product.category,
                    'Price': product.price,
                    'Stock': product.stockQuantity
                    }
                    table.push(obj)
                })
                resolve(table)
            }
        })
    })
}


var test = async () => {
   try{
    console.table(await displayDB())
    }catch(e){
        console.log(e)
    }
    connection.end()
}
test()

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise