My workflow for es6 uses babel and babel-plugin-transform-es2015-modules-system.js to only transform module import/export for use with system.js. I simply use a \"g
I just had the same problem, but realized that THREE does not export THREE but instead all the different modules. Check the section in the three.js file with the exports:
exports.WebGLRenderTargetCube = WebGLRenderTargetCube;
exports.WebGLRenderTarget = WebGLRenderTarget;
exports.WebGLRenderer = WebGLRenderer;
exports.ShaderLib = ShaderLib;
exports.UniformsLib = UniformsLib;
exports.UniformsUtils = UniformsUtils;
exports.ShaderChunk = ShaderChunk;
exports.FogExp2 = FogExp2;
exports.Fog = Fog;
exports.Scene = Scene;
exports.LensFlare = LensFlare;
exports.Sprite = Sprite;
exports.LOD = LOD;
exports.SkinnedMesh = SkinnedMesh;
exports.Skeleton = Skeleton;
exports.Bone = Bone;
exports.Mesh = Mesh;
exports.LineSegments = LineSegments;
exports.Line = Line;
exports.Points = Points;
exports.Group = Group;
... etc
So you can import just the modules you actually need, or as said above: Import all of them via
import * as THREE from 'three.js'
Cheers