使用节点js将mysql结果解析为变量

Question

I'm trying my best to understand nodeJS/typescript and it techniques. But still can't figure out how I can save my databasequery result into a variable and return it. Maybe someone can explain me the problem / help me:

I have a method like this:

public getAllProducts(): ProductArray {
    // returns IConnection from "mysql" and connect
    this.databaseConnection.getConnection().connect();

    var product: any = [];
    this.databaseConnection.getConnection().query('SELECT * FROM product', function (error: any, results:any, fields:any) {
        if (error) throw error;
        product.push(results);
    });



    console.log(product);
    return product;
}

Would be nice if someone can help me out here.

Answer 1

You are not supposed to be able to return a variable from an async function. You should go ahead and read some articles about how to combat callback hell. All your logic that requires this data should be inside the callback function of the query. Some options to make your code look a little bit better is using the async.js module or promises (you can also check the async/await that was added on nodeSJ 7.6.0 version.