Crash on code with private class fields

[Alexsey]

🐛 Bug Report

The code with private class fields is crashing when executing with Jest with error:

>npx jest test
 FAIL  test/index.test.js
  ● Test suite failed to run

    SyntaxError: F:\_\WebstormProjects\jestBug\src\index.js: Unexpected character '#' (4:2)

      2 | 
      3 | class C {
    > 4 |   #x = 42;
        |   ^
      5 |   x() {
      6 |     return this.#x;
      7 |   }

      at Parser.raise (node_modules/@babel/parser/lib/index.js:6387:17)
      at Parser.readToken_numberSign (node_modules/@babel/parser/lib/index.js:6716:12)
      at Parser.getTokenFromCode (node_modules/@babel/parser/lib/index.js:7062:14)
      at Parser.nextToken (node_modules/@babel/parser/lib/index.js:6587:12)
      at Parser.next (node_modules/@babel/parser/lib/index.js:6527:10)
      at Parser.eat (node_modules/@babel/parser/lib/index.js:6532:12)
      at Parser.expect (node_modules/@babel/parser/lib/index.js:7690:10)
      at Parser.parseClassBody (node_modules/@babel/parser/lib/index.js:10670:10)
      at Parser.parseClass (node_modules/@babel/parser/lib/index.js:10645:22)
      at Parser.parseStatementContent (node_modules/@babel/parser/lib/index.js:9942:21)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        2.434s
Ran all test suites matching /test/i.

But direct run of the file under test works fine:

>node src/index.js
42

To Reproduce

Steps to reproduce the behavior:

1. Create src/index.js

'use strict'

class C {
  #x = 42;
  x() {
    return this.#x;
  }
}

console.log(new C().x())

module.exports = C

2. Create test/index.test.js

'use strict'

const C = require('../src')

test('test', () => {
  expect(new C().x()).toEqual(42) //?
})

3. Run npx jest test

Expected behavior

Should have no error

Link to repl or repo (highly encouraged)

https://github.com/Alexsey/jestBug

envinfo

npx: installed 1 in 2.239s

  System:
    OS: Windows 10
    CPU: (4) x64 Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz
  Binaries:
    Node: 12.10.0 - C:\Program Files\nodejs\node.EXE
    npm: 6.11.3 - C:\Program Files\nodejs\npm.CMD

[SimenB]

Roundabout duplicate of #6829 and #8497. This is babel throwing - either disable babel or add the syntax plugin.

I recommend following babel/babel#7660 which I think is the only non ad hoc solution to this

[piranna]

I recommend following babel/babel#7660 which I think is the only non ad hoc solution to this

I've read that issue but got no idea what should I do... can you explain it a little bit about how to support Node.js features with Jest without transpiling?

[github-actions]

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