remove highlight if the higlight atoms are empty

src/plugin/depiction.ts

@@ -112,32 +112,31 @@ class Depiction {
      * @memberof Depiction
      */
     public highlightSubgraph(atoms: Array<string>, color: string = undefined) {
-        if (!this.atoms || !atoms) return;
-
+        if (!this.atoms) return;
         this.highlight.selectAll('*').remove();
-
-        color = color ? color : "#BFBFBF";
-        let atomsToHighlight = this.atoms.filter(x => atoms.includes(x.name));
-
-        this.highlight.selectAll()
-            .data(atomsToHighlight)
-            .enter()
-            .append('circle')
-            .attr('r', '16.12')
-            .attr('cx', x => x.position.x)
-            .attr('cy', x => x.position.y)
-            .attr('style', `fill:${color};fill-rule:evenodd;stroke:${color};stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1`);
-
-        let bondsToHighlight = this.bonds.filter(x => atoms.includes(x.bgn.name) && atoms.includes(x.end.name))
-
-        this.highlight.selectAll()
-            .data(bondsToHighlight)
-            .enter()
-            .append('path')
-            .attr('d', x => `M ${x.bgn.position.x},${x.bgn.position.y} ${x.end.position.x},${x.end.position.y}`)
-            .attr('style', `fill:none;fill-rule:evenodd;stroke:${color};stroke-width:22px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1`)
-    }
-    
+        if(atoms){
+            color = color ? color : "#BFBFBF";
+            let atomsToHighlight = this.atoms.filter(x => atoms.includes(x.name));
+
+            this.highlight.selectAll()
+                .data(atomsToHighlight)
+                .enter()
+                .append('circle')
+                .attr('r', '16.12')
+                .attr('cx', x => x.position.x)
+                .attr('cy', x => x.position.y)
+                .attr('style', `fill:${color};fill-rule:evenodd;stroke:${color};stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1`);
+
+            let bondsToHighlight = this.bonds.filter(x => atoms.includes(x.bgn.name) && atoms.includes(x.end.name))
+
+            this.highlight.selectAll()
+                .data(bondsToHighlight)
+                .enter()
+                .append('path')
+                .attr('d', x => `M ${x.bgn.position.x},${x.bgn.position.y} ${x.end.position.x},${x.end.position.y}`)
+                .attr('style', `fill:none;fill-rule:evenodd;stroke:${color};stroke-width:22px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1`)
+        }
+    }    
     /**
      * Adds circles around atoms corresponding to the value of 
      * their weights.The size, color and number of crcles around