Private methods in class fields

[morten-krogh]

This class illustrates the issue

class A {
    pub = this.#priv;

    #priv() {
        console.log('Inside #priv');
    }
}

There is a private method #priv which is being referenced in the class field initializer for pub.

Transpiling with esbuild from ESNEXT to ES6 gives the following

var _priv, priv_fn;
var A = class {
  constructor() {
    __publicField(this, "pub", __privateMethod(this, _priv, priv_fn));
    _priv.add(this);
  }
};
_priv = new WeakSet();
priv_fn = function() {
  console.log("Inside #priv");
};

The transpiled code gives an error.

The problem is the order of the two lines in the constructor.
The class field initializer

  __publicField(this, "pub", __privateMethod(this, _priv, priv_fn));

runs before the private method is defined

  _priv.add(this);

I would guess the solution is just to make sure all private methods are defined first in the constructor (right after super).
The class fields can then be defined after that.

[evanw]

Thanks for the report. This will be fixed in the next release.