How to Make Class Methods Private in JavaScript?

Starting with ES13/ES2022, you can mark any class method as private by prefixing the method name with # (hash symbol).

For example:

// ES13+
class Foo {
    #privateMethod() {
        return 'foobar';
    }
}

const foo = new Foo();

// SyntaxError
console.log(foo.#privateMethod);

Similarly, you can make getter, setter, generator, async, or async generator methods private as well:

// ES13+
class MyClass {
    #privateMethod() {}
    * #privateGeneratorMethod() {}

    async #privateAsyncMethod() {}
    async * #privateAsyncGeneratorMethod() {}

    get #privateGetter() {}
    set #privateSetter(value) {}
}

In addition to declaring methods as private, you can also:

• Make class fields private;
• Make static class fields private;
• Make static class methods private.