can i pass function as attribute to web component?

Question

I\'m trying to create a native web component for input element. I wanted the component to have custom validation functionality, similar to polymer\'s paper-input custom validato

Answer 1

Just pass it to the constructor. Your custom element statement:

class CustomInput extends HTMLElement {
  constructor(validator) {
    super()
    this.validate = validator
  }

  /* Your Custom Input Methods */
}

And then instantiate your component via the new operator instead of the document.createElement.

Instantiation:

const customInputEl = new CustomInput((inputString) => {
  // your validation code
})

If you want to pass a function to the component, it must mean that you instantiate it via javascript anyway.