Async: Can you use async.series with async / await?

[alexbjorlig]

Can you use async await inside the async.series function?

I did some simple experiments, but they did not work as expected.

[aearly]

Yes, you can! But instead of using a callback, just return a value or throw an error. http://caolan.github.io/async/global.html

[alexbjorlig]

Ok - please forgive me If I misunderstod something 😄 Like this?

    const result = await async.each(openFiles, async (file) => {
        try: {
            await asyncOperation(file);
            return null
        } catch(err) {
            return err
        }
    })

[aearly]

Since async functions automatically convert errors into rejections, unless you wanted to do something special with the error, your example could be reduced to:

    const result = await async.each(openFiles, async (file) => {
        await asyncOperation(file);
    })

[alexbjorlig]

Thank you for the improved snippet. It seems to work in a simple scenario, but in the following setting I can't get it to work:

for (const tasks of fileTasks) {
    const result = await async.each(tasks, async (file) => {
        await asyncOperation(file);
    })
}

I was of the understanding that the for-of loop would allow asynchronous operations?

[aearly]

Since async.each doesn't return a Promise, you can't await it.

[alexbjorlig]

Ahh ok. So using the for-of async/await option is not a good pattern with async. Do you now if this is on the roadmap for async?

[aearly]

There is some mad science planned. 😉

[aearly]

Or util.promisify() 😉

(or pify())

[oznekenzo]

Why does this go from a question about async.series to async.each?

[maxrks]

const _async = require('async');
const _ = require('lodash');

public doSomething = async(num) : Promise<any> => {
     return num*num + 1;
} 

public async getResults() {
    let results = new Array<any>();
    let tasks = [];

    try {
      const list = [1,2,3,4,5,6,7,8,9,10];

      list.forEach((item) => {
        tasks.push((callback) => {
          this.doSomething(item.then(
            (res) => {
              results.push(res);
              callback(null, res);
            }
          );
        })
      })

      results = await new Promise((resolve) => {
        _async.series(tasks, (err, res) => {
          console.log(res);
          if (err) {
            results.push(err);
          }
          resolve(results);
        })
      });
    } catch (err) {
      results.push(err.message);
      console.log(err);
    }

    return _.join(results, '\r\n');
  }

[anhdiepmmk]

@aearly Hey fen could you please tell me which extracly version support async/await ?
I'm using caolan/async version 2.6.0