SyntaxError: Unexpected '#' used outside of class body
The JavaScript exception "Unexpected '#' used outside of class body" occurs when a hash("#") is encountered in an unexpected context, most notablyoutside of a class declaration.Hashes are valid at the beginning of a file as ahashbang comment,or inside of a class as part of a private field. You may encounter this error if you forgetthe quotation marks when trying to access a DOM identifier as well.
Message
SyntaxError: Unexpected '#' used outside of class body.
Error type
What went wrong?
We encountered a# somewhere unexpected. This may be due to code moving around and nolonger being part of a class, a hashbang comment found on a line other than the firstline of a file, or accidentally forgetting the quotation marks around a DOM identifier.
Examples
Missing quotation marks
For each case, there might be something slightly wrong. For example
document.querySelector(#some-element)This can be fixed via
document.querySelector("#some-element");Outside of a class
class ClassWithPrivateField { #privateField; constructor() {}}this.#privateField = 42;This can be fixed by moving the private field back into the class
class ClassWithPrivateField { #privateField; constructor() { this.#privateField = 42; }}