use the data directly

Author: Fil

src/marks/brush.js

@@ -20,7 +20,6 @@ export class Brush extends Mark {
     super(
       data,
       [
-        {name: "picker", value: identity},
         {name: "x", value: x, scale: "x", optional: true},
         {name: "y", value: y, scale: "y", optional: true}
       ],
@@ -32,7 +31,7 @@ export class Brush extends Mark {
   render(
     I,
     {x, y},
-    {x: X, y: Y, picker: J},
+    {x: X, y: Y},
     {marginLeft, width, marginRight, marginTop, height, marginBottom}
   ) {
     let svg;
@@ -59,7 +58,7 @@ export class Brush extends Mark {
             index = index.filter(i => Y[i] >= y0 && Y[i] <= y1);
           }
         }
-        const dots = selection ? Array.from(index, i => J[i]) : data;
+        const dots = selection ? Array.from(index, i => data[i]) : data;
 
         if (svg) {
           svg.value = dots;
@@ -84,7 +83,7 @@ export class Brush extends Mark {
       if (!svg.__brushes) svg.__brushes = [];
       svg.__brushes.push({b: brush, g});
 
-      // initial setup works only on one facet
+      // initial setup works only on the first facet
       if (svg.__brushes.length === 1) {
         if (this.initialSelection) {
           const s = this.initialSelection;