slate/src/utils/scroll-to.js at master · Unhackables/slate · GitHub

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/**
 * Copied from `element-scroll-to`, but edited to account for `window` being
 * inside of iframes.
 *
 * https://github.com/webmodules/element-scroll-to
 */

import getWindow from 'get-window'

function scrollWrapperElements(element, options) {
  let window = getWindow(element)
  let elementRect = element.getBoundingClientRect()
  let wrapper = element.parentNode

  while (wrapper != window.document.body) {
    let wrapperRect = wrapper.getBoundingClientRect()
    let margin = options.margin
    let deltaX = 0
    let deltaY = 0

    if (elementRect.top < wrapperRect.top + margin) {
      deltaY = elementRect.top - wrapperRect.top - margin
    } else if (elementRect.bottom > wrapperRect.bottom - margin) {
      deltaY = elementRect.bottom - wrapperRect.bottom + margin
    }
    if (elementRect.left < wrapperRect.left + margin) {
      deltaX = elementRect.left - wrapperRect.left - margin
    } else if (elementRect.right > wrapperRect.right - margin) {
      deltaX = elementRect.right - wrapperRect.right + margin
    }
    wrapper.scrollTop += deltaY
    wrapper.scrollLeft += deltaX
    wrapper = wrapper.parentNode
  }

  return elementRect
}

function scrollWindow(element, options, elementRect) {
  let window = getWindow(element)
  let margin = options.margin
  let deltaX = 0
  let deltaY = 0

  if (elementRect.top < 0 + margin) {
    deltaY = elementRect.top - margin
  } else if (elementRect.bottom > window.innerHeight - margin) {
    deltaY = elementRect.bottom - window.innerHeight + margin
  }
  if (elementRect.left < 0 + margin) {
    deltaX = elementRect.left - margin
  } else if (elementRect.right > window.innerWidth - margin) {
    deltaX = elementRect.right - window.innerWidth + margin
  }

  window.scrollBy(deltaX, deltaY)
}

function scrollTo(element, options) {
  options = options || {}
  options.margin = options.margin || 0
  let rect = scrollWrapperElements(element, options)
  scrollWindow(element, options, rect)
}

export default scrollTo