select text inside of an element and then copy it to the clipboard

copy.js

function copy(obj) {
  try {
    if (obj) selectContent(obj)
    document.execCommand('copy')
    // clears the current selection
    window.getSelection().removeAllRanges()
  } catch (err) {
    console.log(err)
  }
}

selectContent.js

function selectContent(obj) {
  if (window.getSelection && document.createRange) {
    let sel = window.getSelection()
    let range = document.createRange()
    range.selectNodeContents(obj)
    sel.removeAllRanges()
    sel.addRange(range)
  } else if (document.selection && document.body.createTextRange) {
    let textRange = document.body.createTextRange()
    textRange.moveToElementText(obj)
    textRange.select()
  }
}