delete unnecessary constant variable

src/engine/utils/PointerChecker.js

@@ -15,10 +15,8 @@ class PointerChecker {
   static isPointerOnLine(vs, ve, vScr) {
     // The distance to the line by "x" and "y"
     const MIN_DIST = 10;
-    // The number for define a half of the distance
-    const TWO = 2;
     // Define the center point of the line by "y" coordinate
-    const centerLineY = (vs.y + ve.y) / TWO;
+    const centerLineY = (vs.y + ve.y) / 2;
     // Define the angle slope of the line
     const m = (ve.y - vs.y) / (ve.x - vs.x);
     // Define the intercept of the line
@@ -39,8 +37,8 @@ class PointerChecker {
       vs.x === ve.x &&
       vScr.x <= vs.x + MIN_DIST &&
       vScr.x >= vs.x - MIN_DIST &&
-      vScr.y >= centerLineY - widthY / TWO &&
-      vScr.y <= centerLineY + widthY / TWO
+      vScr.y >= centerLineY - widthY / 2 &&
+      vScr.y <= centerLineY + widthY / 2
     ) {
       return true;
     }