js进行复制功能

function copy(value){
    return new Promise((resolve) => {
        let copyTextArea = null;
        try {
            copyTextArea = document.createElement('textarea');
            copyTextArea.style.height = '0px';
            copyTextArea.style.opacity = '0';
            copyTextArea.style.width = '0px';
            document.body.appendChild(copyTextArea);
            copyTextArea.value = value;
            copyTextArea.select();
            // 防止iphone 7 上复制失败
            document.execCommand('SelectAll');
            document.execCommand('copy');
            resolve(value);
        } finally {
            if (copyTextArea && copyTextArea.parentNode) {
                copyTextArea.parentNode.removeChild(copyTextArea);
            }
        }
    })
}