CODEWITHSUNDEEP
javascriptgoogle-closure-compiler
Nagev
Nagev

Reputation: 13275

google closure compiler parser error with javascript class private field

Getting a parser error with Google Closure Compiler for JavaScript private class fields, even though according to MDN it is widely supported. Extending their example:

class ClassWithPrivateField {
  #privateField;

  constructor() {
    this.#privateField = 42;
  }

  getPrivate() {
    return this.#privateField;
  }
}

console.log("private field", new ClassWithPrivateField().getPrivate());

Saved the above to private.js and ran it in a Node container:

$ docker run \
        --workdir /home/node/app \
        --rm -t -v $PWD:/home/node/app \
        node:18 bash -c \
        "node private.js"
private field 42

The console output shows correctly on the last line above. Now if we run it through google-closure-compiler:

$ docker run \
        --workdir /home/node/app \
        --rm -t -v $PWD:/home/node/app \
        node:18 bash -c \
        "npm i -g google-closure-compiler && google-closure-compiler --js /home/node/app/private.js"

This is the final output:

/home/node/app/private.js:2:2: ERROR - [JSC_PARSE_ERROR] Parse error. '}' expected
  2|   #privateField;
       ^

1 error(s), 0 warning(s)

Looking this up I got the impression from a Github post that this feature is not yet supported, is this correct? Is there a solution or workaround, if I want to use private fields? Even ignoring this error to allow the compilation to continue would be acceptable. Thanks.

Upvotes: 1

Views: 477

Answers (1)

John
John

Reputation: 5468

The Closure Compiler does not yet support private fields. The work around is to not use private fields or to use something like Babel to translate them.

Upvotes: 2

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