fix(color): Correct to not set stroke

Remove setting stroke value on  onover/onout interaction.

Ref #754
Ref #872

spec/internals/color-spec.js

@@ -231,6 +231,8 @@ describe("COLOR", () => {
 	});
 
 	describe("color.onover", () => {
+		const barStrokeColor = "blue";
+
 		before(() => {
 			args = {
 				data: {
@@ -244,6 +246,12 @@ describe("COLOR", () => {
 				},
 				color: {
 					onover: "yellow"
+				},
+				onafterinit: function(ctx) {
+					// set bar stroke color value manually
+					ctx.$.bar.bars
+						.style("stroke", barStrokeColor)
+						.style("stroke-width", 1)
 				}
 			}
 		});
@@ -257,7 +265,8 @@ describe("COLOR", () => {
 
 			shape.each(function() {
 				originalColor.push({
-					fill: this.style.fill
+					fill: this.style.fill,
+					stroke: this.style.stroke
 				});
 			});
 
@@ -273,13 +282,18 @@ describe("COLOR", () => {
 				}
 
 				expect(this.style.fill).to.be.equal(color);
+
+				if (this.tagName === "path") {
+					expect(this.style.stroke).to.be.equal(barStrokeColor);
+				}
 			});
 
 			// check for restoration
 			util.fireEvent(eventRect, "mouseout");
 
 			shape.each(function(d, i) {
 				expect(this.style.fill).to.be.equal(originalColor[i].fill);
+				expect(this.style.stroke).to.be.equal(originalColor[i].stroke);
 		   });
 		};
 

src/internals/color.js

@@ -172,11 +172,7 @@ extend(ChartInternal.prototype, {
 		let color = isOver ? onover : $$.color;
 
 		if (isObject(color)) {
-			color = d => {
-				const id = d.id;
-
-				return id in onover ? onover[id] : $$.color(id);
-			};
+			color = ({id}) => (id in onover ? onover[id] : $$.color(id));
 		} else if (isString(color)) {
 			color = () => onover;
 		}
@@ -187,12 +183,7 @@ extend(ChartInternal.prototype, {
 				.style("fill", color(d));
 		} else {
 			$$.main.selectAll(`.${CLASS.shape}-${d}`)
-				.each(function(d) {
-					const val = color(d);
-
-					this.style.stroke = val;
-					this.style.fill = val;
-				});
+				.style("fill", color);
 		}
 	}
 });