为什么这个import（）承诺在require（）正常工作时被拒绝？

我的代码如下：

'use strict';

import('mysql').then(result => console.log('then'))
    .catch(error => console.log('catch'));

console.log(require('mysql'));

When I run node thisScript.js, the console output is this:

{
  createConnection: [Function: createConnection],
  createPool: [Function: createPool],
  createPoolCluster: [Function: createPoolCluster],
  createQuery: [Function: createQuery],
  escape: [Function: escape],
  escapeId: [Function: escapeId],
  format: [Function: format],
  raw: [Function: raw]
}
catch

If I remove the line with require('mysql'), the console output is just catch.