ParseError: Unexpected token = when trying to save in google Apps Script editor [duplicate]

Question

I reduced the issue to this simple bit of code:

class X {
  static a = 5;
}

I don't know why this is a problem. It seems to be valid code. Any ideas?

Answer 1

Response from Google:

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Apps Script V8 runtime supports EMCA2015 standards which mean static class properties are not supported at the moment. There are two workarounds available:

1 - Assign the property to the class:

// Caused an error
class MyClass {
  static a = 1;
}

// ECMA2015 compatible
class MyClass {}
MyClass.a = 1;

2 - Develop the Apps Scripts with Clasp: https://github.com/google/clasp which also supports TypeScript and many other new features.

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