I'm trying to create a `class` with some fields on Google Apps Scripts. I can't even save the file. From what I understand of this [SO answer](https://stackoverflow.com/questions/57608525/what-are-class-fields-in-javascript), I'm using the correct syntax for class fields.

[V8 runtime](https://developers.google.com/apps-script/guides/v8-runtime#classes) is enabled.

The error:

```none
Syntax error: ParseError: Unexpected token = line: 5 file: Airtable_Class.gs

```

Line 5 is: `foo = "bar";`

Here's the whole code:

```
class FieldsTest{
  foo = "bar";
}

```