style(mapper2d): removed unused imports, const fixes, lonely-if

Fixed newly introduced formatting errors like unused import, const declaration, only if in an else
statement.

Author: sankhesh

Sources/Rendering/Core/Mapper2D/index.js

@@ -10,13 +10,14 @@ import Constants from 'vtk.js/Sources/Rendering/Core/Mapper/Constants';
 
 const { ColorMode, ScalarMode, GetArray } = Constants;
 const { VectorMode } = vtkScalarsToColors;
+const { VtkDataTypes } = vtkDataArray;
 
 /**
  * Increase by one the 3D coordinates
  * It will follow a zigzag pattern so that each coordinate is the neighbor of the next coordinate
  * This enables interpolation between two texels without issues
  * Note: texture coordinates can't be interpolated using this pattern
- * @param {vec3} coordinates The 3D coordinates using integers for each coorinate
+ * @param {vec3} coordinates The 3D coordinates using integers for each coordinate
  * @param {vec3} dimensions The 3D dimensions of the volume
  */
 function updateZigzaggingCoordinates(coordinates, dimensions) {
@@ -438,7 +439,7 @@ function vtkMapper2D(publicAPI, model) {
         scalars.getDataType() === VtkDataTypes.UNSIGNED_CHAR) ||
       model.colorMode === ColorMode.DIRECT_SCALARS
     ) {
-      // Don't use texture is direct coloring using RGB unsigned chars is
+      // Don't use texture if direct coloring using RGB unsigned chars is
       // requested.
       return false;
     }

Sources/Rendering/OpenGL/PolyDataMapper2D/index.js

@@ -3,7 +3,6 @@ import { mat4 } from 'gl-matrix';
 
 import * as macro from 'vtk.js/Sources/macros';
 import vtkHelper from 'vtk.js/Sources/Rendering/OpenGL/Helper';
-import vtkMapper2D from 'vtk.js/Sources/Rendering/Core/Mapper2D';
 import vtkPoints from 'vtk.js/Sources/Common/Core/Points';
 import vtkPolyData2DFS from 'vtk.js/Sources/Rendering/OpenGL/glsl/vtkPolyData2DFS.glsl';
 import vtkPolyData2DVS from 'vtk.js/Sources/Rendering/OpenGL/glsl/vtkPolyData2DVS.glsl';
@@ -18,8 +17,6 @@ import { DisplayLocation } from 'vtk.js/Sources/Rendering/Core/Property2D/Consta
 
 import { registerOverride } from 'vtk.js/Sources/Rendering/OpenGL/ViewNodeFactory';
 
-import { ScalarMode } from 'vtk.js/Sources/Rendering/Core/Mapper/Constants';
-
 const { primTypes } = vtkHelper;
 const { Filter, Wrap } = vtkOpenGLTexture;
 const { vtkErrorMacro } = macro;
@@ -353,14 +350,12 @@ function vtkOpenGLPolyDataMapper2D(publicAPI, model) {
           '  opacity = opacity*vertexColorVSOutput.a;',
         ])
       ).result;
-    } else {
-      if (model.renderable.getAreScalarsMappedFromCells()) {
-        colorImpl = colorImpl.concat([
-          '  vec4 texColor = texture2D(texture1, tcoordVCVSOutput.st);',
-          '  diffuseColor = texColor.rgb;',
-          '  opacity = opacity*texColor.a;',
-        ]);
-      }
+    } else if (model.renderable.getAreScalarsMappedFromCells()) {
+      colorImpl = colorImpl.concat([
+        '  vec4 texColor = texture2D(texture1, tcoordVCVSOutput.st);',
+        '  diffuseColor = texColor.rgb;',
+        '  opacity = opacity*texColor.a;',
+      ]);
     }
 
     colorImpl = colorImpl.concat([
@@ -597,7 +592,7 @@ function vtkOpenGLPolyDataMapper2D(publicAPI, model) {
         model.internalColorTexture &&
         cellBO.getProgram().isUniformUsed('texture1')
       ) {
-        let texUnit = model.internalColorTexture.getTextureUnit();
+        const texUnit = model.internalColorTexture.getTextureUnit();
         if (texUnit > -1) {
           cellBO
             .getProgram()