等待似乎不是在等待我的函数中的结果

Question

I realize this sort of question has been asked here, and I have done extensive research before I posted this question.

I have seven operations that need to be run in order. Most are database related, so they may take some time to finish up.

1. getLiveItems => puppeteer page (avg 10 seconds)

2. getOldItems => mySQL query

3. getNewItems => mySQL query

4. compareItems => lodash compare

5. saveOldItems => mySQL insert query

6. saveNewItems => mySQL insert query

7. notifyUser => puppeteer open page

I understand I need to either use a callback, or a promise. But I can't even get past the first two operations using either method.

Here is my latest attempt.

var oldItems, newItems;


var getoldItems = async function(callback) {
    await connection.query('SELECT * FROM items', function(err, rows) {
        if (err) {
            throw err;
        } else 
            callback(null, rows);
    });
}

var getnewItems = async function(callback) {
    await connection.query('SELECT * FROM newItems', function(err, rows) {
        if (err) {
            throw err;
        } else 
            callback(null, rows);
    });
}



const init = async function(){

    await getoldItems(function(err, content) {
        if(err){
            console.log(err);

        } else {
            oldItems = content;
            return oldItems;
        }
    })

    await getnewItems(function(err, content) {
        if(err){
           // console.log(err);  
        } else {
            newItems = content;
            return newItems;
        }
    })

    return;

}

( async function() {
 await init();
 console.log(oldItems);
 console.log(newItems);   
});

I get no output. No errors, either.

I'm really confused. I have read, and read about this topic, but I am missing something fundamental.

This is how my mind is processing my script, thus the reason I wrote it that way...

I am going to await the results from the init function, which does the following...

I am going to wait for the results of getOldItems and then move on to waiting for the results of getNewItems. Then, I am going to return back to Init and console out both results.

What Am I Missing?!

Thank you in advance.

Frustrated In Florida, John

Answer 1

You're using callbacks, not Promises, so your awaits aren't actually doing anything.
You have a few choices: - switch to all callbacks - wrap your callbacks with Promises - use a db library that supports Promises natively

A few Promise-enabled mysql libraries:
https://www.npmjs.com/package/mysql2
https://www.npmjs.com/package/promise-mysql