fix(Chart): Handle nullish properties from API extendings safely

Chart APIs having null/undefined properties should not break the chart construction now

Ref #2132
Close #2134

AUTHORS.txt

@@ -47,3 +47,4 @@ Marc Faber <faber@genodata.de>
 Donald Pipowitch <pipo@senaeh.de>
 Sung Oh Park <sung-oh.park@navercorp.com>
 Adrian Schmutzler <dev@schmutzler.it>
+Aziz Gazanchiyan <ZIZ@KMDPoland.pl>

src/Chart/Chart.ts

@@ -4,7 +4,7 @@
  */
 import ChartInternal from "../ChartInternal/ChartInternal";
 import {loadConfig} from "../config/config";
-import {extend, isFunction} from "../module/util";
+import {extend, isFunction, notEmpty} from "../module/util";
 
 import apiChart from "./api/chart";
 import apiColor from "./api/color";
@@ -89,12 +89,15 @@ export default class Chart {
 			Object.keys(fn).forEach(key => {
 				const isFunc = isFunction(fn[key]);
 				const isChild = target !== argThis;
-				const hasChild = Object.keys(fn[key]).length > 0;
+				const isNotNil = notEmpty(fn[key]);
+				const hasChild = isNotNil && Object.keys(fn[key]).length > 0;
 
 				if (isFunc && ((!isChild && hasChild) || isChild)) {
 					target[key] = fn[key].bind(argThis);
-				} else if (!isFunc) {
+				} else if (isNotNil && !isFunc) {
 					target[key] = {};
+				} else {
+					target[key] = fn[key];
 				}
 
 				hasChild && bindThis(fn[key], target[key], argThis);

test/internals/bb-spec.ts

@@ -8,7 +8,8 @@ import sinon from "sinon";
 import bb from "../../src";
 import util from "../assets/util";
 import CLASS from "../../src/config/classes";
-import {convertInputType} from "../../src/module/util";
+import Chart from "../../src/Chart/Chart";
+import {convertInputType, extend} from "../../src/module/util";
 
 describe("Interface & initialization", () => {
 	let chart;
@@ -113,6 +114,29 @@ describe("Interface & initialization", () => {
 
 			expect(chart.$.chart.classed(bindtoClassName)).to.be.true;
 		});
+
+		it("should bind correctly with nullish properties", () => {
+			const options = {
+				data: {
+					columns: [["data1", 0]]
+				}
+			};
+
+			class Extended extends Chart {
+				nullProperty;
+				voidProperty;
+			}
+
+			extend(Chart.prototype, {
+				nullProperty: null,
+				voidProperty: undefined
+			});
+
+			const extendedInstance = new Chart(options);
+
+			expect((extendedInstance as Extended).nullProperty).to.be.null;
+			expect((extendedInstance as Extended).voidProperty).to.be.undefined;
+		});
 	});
 
 	describe("auto resize", () => {