fix(bar): fix bar radius for zero value

In a process where values dynamically change from positive
value to zero, the transition appears wrongly if the Arc command
removed from the exist path.
To mitigate, maintain Arc command from path on this data flow.

Fix #2642

src/ChartInternal/shape/bar.ts

@@ -102,7 +102,7 @@ export default {
 		return [
 			$$.$T(bar, withTransition, getRandom())
 				.attr("d", d => (isNumber(d.value) || $$.isBarRangeType(d)) && drawFn(d))
-				.style("fill", this.color)
+				.style("fill", $$.color)
 				.style("opacity", null)
 		];
 	},
@@ -154,10 +154,10 @@ export default {
 			let radius = 0;
 
 			const isGrouped = $$.isGrouped(d.id);
-			const hasRadius = d.value !== 0 && getRadius;
-			const isRadiusData = hasRadius && isGrouped ? $$.isStackingRadiusData(d) : false;
+			// const hasRadius = d.value !== 0 && getRadius;
+			const isRadiusData = getRadius && isGrouped ? $$.isStackingRadiusData(d) : false;
 
-			if (hasRadius && (!isGrouped || isRadiusData)) {
+			if (getRadius && (!isGrouped || isRadiusData)) {
 				const index = isRotated ? indexY : indexX;
 				const barW = points[2][index] - points[0][index];
 
@@ -188,9 +188,16 @@ export default {
 	 */
 	isStackingRadiusData(d: IDataRow): boolean {
 		const $$ = this;
-		const {config, data} = $$;
+		const {$el, config, data, state} = $$;
 		const {id, index, value} = d;
 
+		// when the data is hidden, check if has rounded edges
+		if (state.hiddenTargetIds.indexOf(id) > -1) {
+			const target = $el.bar.filter(d => d.id === id && d.value === value);
+
+			return !target.empty() && /a\d+/i.test(target.attr("d"));
+		}
+
 		// Find same grouped ids
 		const keys = config.data_groups.find(v => v.indexOf(id) > -1);
 

test/shape/bar-spec.ts

@@ -773,9 +773,9 @@ describe("SHAPE BAR", () => {
 		});
 
 		// https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Paths#arcs
-		it("for zero value, Arc 'a' path command shouldn't be added ", () => {
-			expect(chart.$.bar.bars.attr("d").indexOf("a") === -1).to.be.true;
-		});
+		// it("for zero value, Arc 'a' path command shouldn't be added ", () => {
+		// 	expect(chart.$.bar.bars.attr("d").indexOf("a") === -1).to.be.true;
+		// });
 
 		it("set options", () => {
 			args.data.columns[0][0] = 2;
@@ -843,6 +843,37 @@ describe("SHAPE BAR", () => {
 
 			expect(radiusCount).to.be.equal(8);
 		});
+
+		it("set options", () => {
+			args = {				
+				data: {
+					columns: [
+						["d3", 3, 5, 8, 3, 9, 2]
+					],
+					type: "bar",
+					labels: false
+				},
+				bar: {
+					padding: 2,
+					radius: {
+						ratio: 0.2
+					}
+				}
+			};
+		});
+
+		it("path data should remain with Arc command with value 0(zero).", done => {
+			// when
+			chart.load({
+				columns: [["d3", 3, 5, 8, 3, 9, 0]],
+				done: function() {
+					const d = this.$.bar.bars.filter(":last-child").attr("d");
+
+					expect(/\sa\d+/.test(d)).to.be.true;
+					done();
+				}
+			});
+		})
 	});
 
 	describe("bar position", () => {