# Return output to parent in child\_process

**URL:** <https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304>\
**Category:** General\
**Created:** [8 March 2023 15:27 UTC](https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304 "2023-03-08T15:27:20Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![denissanga](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/denissanga/32/48346_2.png) [@denissanga](https://discourse.nodered.org/u/denissanga)\
**Post date:** [8 March 2023 15:27 UTC](https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304/1 "2023-03-08T15:27:20Z")

</div>

hi all, I'm writing a function with chil\_process.exec and I would return a value to parent

```auto
var dir = flow.get("mntFolderName")

let checkOut
try {
      var mntCheckOutput = exec('mountpoint ' + dir, (error, stdout) => {
          if (error) {
              checkOut = false;
              return checkOutput;
          }
          if (!stdout.includes("is not a mountpoint")) {
              checkOut = true;
              return checkOutput;
          } else {
              checkOut = false;
              return checkOutput
          }
      });
      node.warn(mntCheckOutput)
  } catch (error) {
      checkOut = false;
      return
  }

```

the node.warn show me "[object object]"

How can i read true or false in the main project?

many thanks in advance

---

<div class="post-metadata">

**Author:** ![ralphwetzel](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ralphwetzel/32/53713_2.png) [@ralphwetzel](https://discourse.nodered.org/u/ralphwetzel)\
**Post date:** [8 March 2023 19:52 UTC](https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304/2 "2023-03-08T19:52:48Z")

</div>

Hi @denissanga !

`node.warn` does what you told it to do; it tries to serialize `mntCheckOutput` to debug it to the log file.

`exec` yet runs async. To return `checkOut`, you may try to do something like:

```auto
    if (error) {
        checkOut = false;
        msg.payload = checkOut
        node.send(msg)
        node.done();
        return;
    }

```

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [8 March 2023 20:38 UTC](https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304/3 "2023-03-08T20:38:03Z")

</div>

Warn with an object or array...

```auto
node.warn({mntCheckOutput})

```

Or

```auto
node.warn(['mntCheckOutput',mntCheckOutput])

```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [7 May 2023 20:38 UTC](https://discourse.nodered.org/t/return-output-to-parent-in-child-process/76304/4 "2023-05-07T20:38:25Z")

</div>

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