Remove unused variable (tidy-up, unrelated to the main issue)

Issue 4686
Explicitly check for single isolated points when creating paths for
'straight' and 'smooth' curves. Curve type 'monotoneCubic' already
does this intrinsically due to the different algorithm employed.

src/charts/Line.js

@@ -794,7 +794,6 @@ class Line {
     curve,
     isRangeStart,
   }) {
-    let w = this.w
     let graphics = new Graphics(this.ctx)
     const areaBottomY = this.areaBottomY
     let rangeArea = type === 'rangeArea'
@@ -952,11 +951,26 @@ class Line {
               }
               areaPath = graphics.move(pX, pY)
 
+              // Check for single point
+              if (series[i][j + 1] === null) {
+                linePath += graphics.line(pX, pY);
+                areaPath += graphics.line(pX, pY);
+                linePaths.push(linePath);
+                areaPaths.push(areaPath);
+                // Stay in pathState = 0;
+                break
+              }
               pathState = 1
               if (j < series[i].length - 2) {
                 let p = graphics.curve(pX + length, pY, x - length, y, x, y)
                 linePath += p
                 areaPath += p
+                // Check for single point
+                if (series[i][j + 1] === null) {
+                  linePaths.push(linePath)
+                  areaPaths.push(areaPath)
+                  pathState = 0
+                }
                 break
               }
             // Continue on with pathState 1 to finish the path and exit
@@ -1034,6 +1048,15 @@ class Line {
               }
               areaPath = graphics.move(pX, pY)
 
+              // Check for single point
+              if (series[i][j + 1] === null) {
+                linePath += graphics.line(pX, pY);
+                areaPath += graphics.line(pX, pY);
+                linePaths.push(linePath);
+                areaPaths.push(areaPath);
+                // Stay in pathState = 0
+                break
+              }
               pathState = 1
               if (j < series[i].length - 2) {
                 let p = pathToPoint(curve, x, y)