Typescript Proj4-TypeError:lib_namespaceObject不是函数

我试图用proj4转换一些坐标，但是我得到了这个错误

Uncaught（in promise）类型错误：lib_namespaceObject不是函数

proj4是从typescript模块内部调用的。 proj4版本：2.6.3

我的代码：

import * as proj4 from 'proj4'
import * as atlas from 'azure-maps-control';

//...

fetch('...')
  .then(response => response.json())
  .then((data: atlas.data.FeatureCollection) => {
     data.features = data.features.filter(f => f.geometry);
     data.features.forEach(f => {
       let from = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs";
       let to = "+title=WGS 84 (long/lat) +proj=longlat +ellps=WGS84 +datum=WGS84 +units=degrees";

       f.geometry.coordinates[0] = proj4(from, to, f.geometry.coordinates[0] as any);
       f.geometry.coordinates[1] = proj4(from, to, f.geometry.coordinates[1] as any);
     });
  });

错误出现在第行：

---

f.geometry.coordinates[0]=proj4（from，to，f.geometry.coordinates[0]）

我现在让它工作了。必须将导入更改为

import proj4 from 'proj4'