Underscore prefixes for "private" properties

From the main section:

Use a leading underscore _ when naming private properties.

From the React section:

Do not use underscore prefix for internal methods of a React component.

These two seem a bit inconsistent.

[ljharb]

@taion if your goal is helpful suggestions, then name it this.private_address_do_not_use, or SECRET_DOM_DO_NOT_USE_OR_YOU_WILL_BE_FIRED. Naming it _address is just obscure.

[nicbou]

In principle, yes, but underscores are a widely understood indicator that a variable is “private”. You don’t walk through a door with a sock on the handle, even if it’s unlocked.

Since there are no private properties in ES6 classes, how can I indicate “private” methods and properties? This is especially problematic with getters/setters in ES6, since it needs to be stored in a separate variable.

// Simplified example
export class User {
  get address() { return this._address; }
  set address(address) { this._address = address; }
}