no-unused-private-class-members

Nothing outside a class can reach its #private fields and methods. If nothing inside the class uses one either, it's dead code, or the code that should use it is missing.

A field that's only written to counts as unused, because the statements this.#count = 1 and this.#count++ never read the value.

If nothing refers to the member at all, --fix-suggestions removes it, unless it has a decorator or an initializer that runs other code, like #sent = sendEmail().

This rule is on by default.

Configure

On by default as a warning. To turn it off:

[lint.rules]
"no-unused-private-class-members" = "off" # or "error"

Examples

Reported:

class Counter {
  #count = 0;
  #step = 1;

  #log() {
    console.log("changed");
  }

  increment() {
    this.#count++;
  }
}

Not reported:

class Counter {
  #count = 0;
  #step = 1;

  #log() {
    console.log("changed to", this.#count);
  }

  increment() {
    this.#count += this.#step;
    this.#log();
  }
}

In TypeScript files, setting this rule runs @typescript-eslint/no-unused-private-class-members instead. It also checks private members:

class Counter {
  private count = 0;
}