paste.js

import {fireEvent} from '@testing-library/dom'
import {
  setSelectionRangeIfNecessary,
  calculateNewValue,
  eventWrapper,
} from './utils'

function paste(
  element,
  text,
  init,
  {initialSelectionStart, initialSelectionEnd} = {},
) {
  if (element.disabled) return
  if (typeof element.value === 'undefined') {
    throw new TypeError(
      `the current element is of type ${element.tagName} and doesn't have a valid value`,
    )
  }
  eventWrapper(() => element.focus())

  // by default, a new element has it's selection start and end at 0
  // but most of the time when people call "paste", they expect it to paste
  // at the end of the current input value. So, if the selection start
  // and end are both the default of 0, then we'll go ahead and change
  // them to the length of the current value.
  // the only time it would make sense to pass the initialSelectionStart or
  // initialSelectionEnd is if you have an input with a value and want to
  // explicitely start typing with the cursor at 0. Not super common.
  if (element.selectionStart === 0 && element.selectionEnd === 0) {
    setSelectionRangeIfNecessary(
      element,
      initialSelectionStart ?? element.value.length,
      initialSelectionEnd ?? element.value.length,
    )
  }

  fireEvent.paste(element, init)

  if (!element.readOnly) {
    const {newValue, newSelectionStart} = calculateNewValue(text, element)
    fireEvent.input(element, {
      inputType: 'insertFromPaste',
      target: {value: newValue},
    })
    setSelectionRangeIfNecessary(element, {
      newSelectionStart,
      newSelectionEnd: newSelectionStart,
    })
  }
}

export {paste}