chore(util): simplify Geometry#pointsAligned helper

lib/util/Geometry.js

@@ -1,6 +1,5 @@
 import {
-  every,
-  isArray
+  every
 } from 'min-dash';
 
 /**
@@ -56,65 +55,42 @@ var ALIGNED_THRESHOLD = 2;
 /**
  * Check whether two points are horizontally or vertically aligned.
  *
- * @param {Array<Point>|Point}
- * @param {Point}
+ * @param {Point[]|Point} a
+ * @param {Point} [b]
  *
- * @return {string|boolean}
+ * @return {'h'|'v'|false} axis or false
  */
 export function pointsAligned(a, b) {
-  var points;
+  var points = Array.from(arguments).flat();
 
-  if (isArray(a)) {
-    points = a;
-  } else {
-    points = [ a, b ];
-  }
-
-  if (pointsAlignedHorizontally(points)) {
-    return 'h';
-  }
+  const axisMap = {
+    'x': 'v',
+    'y': 'h'
+  };
 
-  if (pointsAlignedVertically(points)) {
-    return 'v';
+  for (const [ axis, orientation ] of Object.entries(axisMap)) {
+    if (pointsAlignedOnAxis(axis, points)) {
+      return orientation;
+    }
   }
 
   return false;
 }
 
-export function pointsAlignedHorizontally(a, b) {
-  var points;
-
-  if (isArray(a)) {
-    points = a;
-  } else {
-    points = [ a, b ];
-  }
-
-  var firstPoint = points.slice().shift();
-
-  return every(points, function(point) {
-    return Math.abs(firstPoint.y - point.y) <= ALIGNED_THRESHOLD;
-  });
-}
-
-export function pointsAlignedVertically(a, b) {
-  var points;
-
-  if (isArray(a)) {
-    points = a;
-  } else {
-    points = [ a, b ];
-  }
-
-  var firstPoint = points.slice().shift();
+/**
+ * @param { 'x' | 'y' } axis
+ * @param { Point[] } points
+ *
+ * @return {boolean}
+ */
+export function pointsAlignedOnAxis(axis, points) {
+  const referencePoint = points[0];
 
   return every(points, function(point) {
-    return Math.abs(firstPoint.x - point.x) <= ALIGNED_THRESHOLD;
+    return Math.abs(referencePoint[axis] - point[axis]) <= ALIGNED_THRESHOLD;
   });
 }
 
-
-
 /**
  * Returns true if the point p is inside the rectangle rect
  *