[QObjectList] Cannot read property 'forEach' of null in javascript

zosskr

Hi,
I got "Cannot read property 'forEach' of null" error message from javascript when I try to list of QObjectList using forEach.

Do you know how to enumerate the list of QObject from QObjectList in javascript?

Looks like "forEach" is not supported.

Thank you.

sierdzio

A standard loop should work fine:

for (var i = 0; i < list.length; ++i) {
  console.log(list[i])
}

Also, try Qt 5.12.1, JS support was improved there, perhaps forEach would work.

JonB

@zosskr said in [QObjectList] Cannot read property 'forEach' of null in javascript:

Cannot read property 'forEach' of null" error message

That implies in any case that your QObjectList variable is null, so you need to check that first....

zosskr

@sierdzio : Thank you for the answer. I will check with your suggestions. :)

zosskr

@JonB : Thank you for the answer. I already verified the object is valid. I think QObjectList is not supported in 5.12.0 for JS. may need to check with higher version.

zosskr

@sierdzio Unfortunately, Qt 5.12.1 does not work also.

JKSH

@zosskr said in [QObjectList] Cannot read property 'forEach' of null in javascript:

I think QObjectList is not supported in 5.12.0 for JS.

QObjectList is definitely supported by QJSEngine in Qt 5.12.

How did you pass the list into JavaScript?

I already verified the object is valid.

How did you do that?

JonB

@zosskr
I am with @JKSH on this: how do you actually know the object is valid? Because when JS says

"Cannot read property 'forEach' of null" error message from javascript when I try to list of QObjectList using forEach.

that (should) mean that the lhs of whatever you are calling forEach() on has the value null....