How do I iterate of the object containing queries, and execute them all

Question

I have an object that looks like this:

let queries = [
  {
    name: "checkUsers",
    query: 'select * from users where inactive = 1'
  },
  {
    name: "checkSubscriptions",
    query: 'select * from subscriptions where invalid = 1'
  }
]

I am making an AWS Lambda function that will iterate these queries, and if any of them returns a value, I will send an email.

I have come up with this pseudo code:

for (let prop in queries) {  

  const result = await mysqlConnector.runQuery(prop.query).catch(async error => {
    // handle error in query    
  });

  if (result.length < 0){
    // send email
  }
}

return;

I am wondering is this ideal approach? I need to iterate all the object queries.

Just for clarification, do you want to send mail every time if a response returns? or just when one of the response return first? — Sándor Bakos, Feb 17 '20 at 08:58
For all queries that return something, I will send the email. Others will be ignored. — Amiga500, Feb 17 '20 at 09:01
I would map the "queries" array's object into request promises, and would use the promise.all with a little workaround, or if the lambda node runtime is 12.9 or higher I would use promise.allSettled. — Sándor Bakos, Feb 17 '20 at 09:08

score 1 · Answer 1 · answered Feb 17 '20 at 09:11

I don't see anything wrong with what you are trying to achieve but there are few changes you could do

Try to use Promise.all if you can. This will speed up the overall process as things will execute in parallel. It will depend on number of queries as well.
Try leverage executing multiple statements in one query. This way you will make one call and then you can add the logic to identify. Check here

How do I iterate of the object containing queries, and execute them all

1 Answers1