czy-avue-form-design/packages/avue/code/src/plugin/clipboard/index.js

Vue3.0版本，因Avue还存在一些bug，请慎重使用。

function select(element) {
  let selectedText;

  if (element.nodeName === 'SELECT') {
    element.focus();

    selectedText = element.value;
  } else if (element.nodeName === 'INPUT' || element.nodeName === 'TEXTAREA') {
    let isReadOnly = element.hasAttribute('readonly');

    if (!isReadOnly) {
      element.setAttribute('readonly', '');
    }

    element.select();
    element.setSelectionRange(0, element.value.length);

    if (!isReadOnly) {
      element.removeAttribute('readonly');
    }

    selectedText = element.value;
  } else {
    if (element.hasAttribute('contenteditable')) {
      element.focus();
    }

    let selection = window.getSelection();
    let range = document.createRange();

    range.selectNodeContents(element);
    selection.removeAllRanges();
    selection.addRange(range);

    selectedText = selection.toString();
  }

  return selectedText;
}


export default function ({ text }) {
  return new Promise((resolve, reject) => {
    const container = document.body;
    const isRTL = document.documentElement.getAttribute('dir') == 'rtl';
    const fakeElem = document.createElement('textarea');
    fakeElem.style.fontSize = '12pt';
    fakeElem.style.border = '0';
    fakeElem.style.padding = '0';
    fakeElem.style.margin = '0';
    fakeElem.style.position = 'absolute';
    fakeElem.style[isRTL ? 'right' : 'left'] = '-9999px';
    let yPosition = window.pageYOffset || document.documentElement.scrollTop;
    fakeElem.style.top = `${yPosition}px`;
    fakeElem.setAttribute('readonly', '');
    fakeElem.value = text;
    container.appendChild(fakeElem);
    select(fakeElem);
    let succeeded;
    try {
      succeeded = document.execCommand('copy');
      resolve();
    } catch (err) {
      succeeded = false;
      reject();
    }
  })
}