Return in method just showing undefined. How to get the callback?

Question

I have a method with a forEach loop.

This works fine and shows a result list.

Here is the code:

test() {

  os.cpus().forEach(el => {
    if (el.model.search('Intel') === 0) {
      return el.model.match(/i(.*)-/)[1];
    }
  });

}

The forEach has a return and the method return undefined.

I know I need to do a callback but I just don't know how to do this in this code.

How can I get test() to return the result?

Possible duplicate of [Callback after all asynchronous forEach callbacks are completed](https://stackoverflow.com/questions/18983138/callback-after-all-asynchronous-foreach-callbacks-are-completed) — xerx593, Feb 11 '19 at 01:09

score 2 · Accepted Answer · answered Feb 10 '19 at 22:09

2

Use .find instead, and if a match is found, perform the .match( operation:

test() {
  const foundEl = os.cpus().find((el) => el.model.search('Intel') === 0);
  if (foundEl) {
    return foundEl.model.match(/i(.*)-/)[1];
  }
}

Since it looks like el.model is a string, better to use startsWith than .search:

test() {
  const foundEl = os.cpus().find((el) => el.model.startsWith('Intel'));
  if (foundEl) {
    return foundEl.model.match(/i(.*)-/)[1];
  }
}

You generally have to use callbacks for asynchronous operations. With synchronous operations (such as this one), you can simply return the value.

answered Feb 10 '19 at 22:09

CertainPerformance

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os.cpus() doesn't have a property "find" – Charlie Feb 10 '19 at 22:14
It's still returning undefined – Feb 10 '19 at 22:16
os.cpus() returns an array, so how could it not have a "find" method exactly? – Azami Feb 10 '19 at 22:16
1

@Charlie It doesn't? I thought [`The os.cpus() method returns an array of objects containing information about each logical CPU core.`](https://nodejs.org/api/os.html#os_os_cpus)? – CertainPerformance Feb 10 '19 at 22:16
@KevinPorche It will return `undefined` if no elements fulfilled the `.find` test. – CertainPerformance Feb 10 '19 at 22:16
it does but you have to extract it first as Kenvin states, is returning undefined – Charlie Feb 10 '19 at 22:18
1

@Charlie The `foundEl` will containing the extracted CPU object, if a matching one is found. What further extraction are you describing? – CertainPerformance Feb 10 '19 at 22:21
lol you're right, it seems the reason he still gets undefined is because his processor is not intel – Charlie Feb 10 '19 at 22:22

Return in method just showing undefined. How to get the callback?

1 Answers1