参看这个 https://blog.csdn.net/supermapsupport/article/details/109294147 去搭建的
node 14.2.0 npm 6.14.17
你这边npm安装11.0.0的leaflet是否有问题?
npm install @supermap/iclient-ol@11.0.0
Leaflet引用1.7.1
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.7.1/leaflet.css" />