Add stricter type-checking on helper functions

Author: umairnadeem

src/components/_helpers/line.js

@@ -23,7 +23,7 @@ export const findMidpoints = ([tuple], index, points) => {
   return (tuple + next) / 2;
 };
 
-export const normalize = (points, compression = 0, xCeil = 0, yCeil = 0) => {
+export const normalize = (points = [], compression = 0, xCeil = 0, yCeil = 0) => {
   const [xMax, yMax, xMin, yMin] = points.reduce((accum, elem) => ([
     Math.max(elem[0], accum[0]),
     Math.max(elem[1], accum[1]),

src/components/_services/drawPath.js

@@ -6,9 +6,9 @@ const defaultFn = (point) => `L${point.join(',')}`;
  * @param {Function} transform - (optional) A transformation callback function
  * @param {Object} payload - (optional) The payload for the transformation function
  */
-export const drawPath = (points = [], transform = defaultFn, payload) => points
+export const drawPath = (points = [], transform = defaultFn, payload = 0) => points
   .sort((a, b) => a[0] - b[0]) // Sort the points by X values
   .reduce((path, point, index) => (
     index
       ? `${path} ${transform(point, index, points, payload)}`
-      : `M${point.join(',')}`), []);
+      : `M${point.join(',')}`), '');

src/components/_services/findCtrlPoint.js

@@ -32,5 +32,5 @@ export const findCtrlPoint = (smoothing = 0, ...args) => {
   outX -= Math.min(Math.abs(smoothing), 1) * proximity;
   const outY = slope * outX + intercept;
 
-  return [outX, outY];
+  return [outX || 0, outY || 0];
 };

src/components/_transformations/smooth.js

@@ -7,7 +7,7 @@ import { findCtrlPoint } from '../_services';
  * @param {Array.<Array>} points - The entire points array
  * @param {Number} ratio - (optional) A smoothing ratio, from 0 to 1
  */
-export const smooth = (point, index, points, ratio = 0) => `S${findCtrlPoint(
+export const smooth = (point = [0, 0], index = 0, points = [], ratio = 0) => `S${findCtrlPoint(
   ratio,
   points[index - 1],
   point,