How to correctly assign the type of variables (events and html element)?

Question

typescript

There is a code that works, but the IDE swears:

• currentElement can be null
  

export function verifyRequired (event: { target: HTMLInputElement }, ignoreError: boolean = false) {
  updateStepButton(ignoreError)

  const currentElement: HTMLInputElement = event.target
  const parentElement = currentElement.parentNode.querySelector('span')

  if (currentElement.getAttribute('required') && (!currentElement.value || currentElement.value.length < 2)) {
    parentElement.classList.add('show-tooltip')
  } else {
    parentElement.classList.remove('show-tooltip')
  }
}

How to fix this error?

Answer 1

Write it like this:

const parentElement = currentElement.parentNode!.querySelector('span')