SyntaxError: private fields can't be deleted

The JavaScript exception "SyntaxError: private fields can't be deleted" occurs when delete is used on a private element of a class or an object.

Message#

SyntaxError: Private fields can not be deleted (V8-based)
SyntaxError: private fields can't be deleted (Firefox)
SyntaxError: Cannot delete private field X (Safari)

Error type#

{{jsxref("SyntaxError")}}

What went wrong?#

There's code trying to delete a private element (field or method) of an object or a class. This is forbidden by JavaScript—private elements cannot be added or removed on the fly.

Examples#

```js example-bad class MyClass { #myPrivateField; deleteIt() { delete this.#myPrivateField; // SyntaxError: private fields can't be deleted } }

```js example-bad
class MyClass {
  #myPrivateMethod() {
  }
  #deleteIt() {
    delete this.#myPrivateMethod; // SyntaxError: private fields can't be deleted
  }
}

See also#

• Classes
• Private elements