Added extension to some imports.

src/objects/Line.js

@@ -5,7 +5,7 @@ import { Object3D } from '../core/Object3D.js';
 import { Vector3 } from '../math/Vector3.js';
 import { LineBasicMaterial } from '../materials/LineBasicMaterial.js';
 import { BufferGeometry } from '../core/BufferGeometry.js';
-import { Float32BufferAttribute } from '../core/BufferAttribute';
+import { Float32BufferAttribute } from '../core/BufferAttribute.js';
 
 /**
  * @author mrdoob / http://mrdoob.com/

src/objects/LineSegments.js

@@ -1,6 +1,6 @@
 import { Line } from './Line.js';
 import { Vector3 } from '../math/Vector3.js';
-import { Float32BufferAttribute } from '../core/BufferAttribute';
+import { Float32BufferAttribute } from '../core/BufferAttribute.js';
 
 /**
  * @author mrdoob / http://mrdoob.com/