make sure downsample is working for plotting functions

demo/components/victory-zoom-container-demo.js

@@ -135,8 +135,8 @@ export default class App extends React.Component {
   getData() {
     return range(50).map((i) => {
       return {
-        x: i + 20,
-        y: Math.random()
+        a: i + 20,
+        b: Math.random()
       };
     });
   }
@@ -167,7 +167,7 @@ export default class App extends React.Component {
         <CustomChart style={{ parent: parentStyle }} data={allData} maxPoints={120}/>
 
           <VictoryGroup
-            containerComponent={<VictoryZoomContainer dimension="y"/>}
+            containerComponent={<VictoryZoomContainer zoomDimension="y"/>}
             style={{ parent: parentStyle }} data={this.state.transitionData}
           >
             <VictoryLine animate={{ duration: 1500 }} style={{ data: this.state.style }} />
@@ -210,7 +210,8 @@ export default class App extends React.Component {
             containerComponent={
               <VictoryZoomContainer
                 minimumZoom={{ x: 5 }}
-                dimension="x"
+                zoomDimension="x"
+                downsample={10}
                 clipContainerComponent={
                   <VictoryClipContainer clipPadding={{ top: 15, bottom: 15 }}/>
                 }
@@ -222,6 +223,7 @@ export default class App extends React.Component {
                 style={{ parent: parentStyle, data: { fill: "orange" } }}
                 size={15}
                 data={this.state.data}
+                x="a" y="b"
               />
             </VictoryPortal>
           </VictoryChart>
@@ -232,7 +234,8 @@ export default class App extends React.Component {
             containerComponent={
               <VictoryZoomContainer
                 minimumZoom={{ x: 5 }}
-                dimension="x"
+                zoomDimension="x"
+                downsample={10}
                 clipContainerComponent={
                   <VictoryClipContainer clipPadding={{ top: 15, bottom: 15 }}/>
                 }
@@ -243,6 +246,7 @@ export default class App extends React.Component {
               style={{ parent: parentStyle, data: { fill: "orange" } }}
               size={15}
               data={this.state.data}
+              x="a" y="b"
               labels={(d) => d.x}
               labelComponent={<VictoryTooltip/>}
             />
@@ -288,10 +292,11 @@ export default class App extends React.Component {
             <VictoryArea
               style={{ parent: parentStyle, data: { stroke: "#333", fill: "#888", opacity: 0.4 } }}
               data={this.state.data}
+              x="a" y="b"
               interpolation="stepBefore"
             />
             <VictoryAxis/>
-            <VictoryLine data={this.state.data} interpolation="stepBefore"/>
+            <VictoryLine data={this.state.data} x="a" y="b" interpolation="stepBefore"/>
             <VictoryAxis dependentAxis/>
           </VictoryChart>
 

src/components/containers/victory-zoom-container.js

@@ -1,6 +1,6 @@
 import PropTypes from "prop-types";
 import React from "react";
-import { defaults, get } from "lodash";
+import { defaults, isFunction } from "lodash";
 import ZoomHelpers from "./zoom-helpers";
 import {
   VictoryContainer, VictoryClipContainer, Data, PropTypes as CustomPropTypes
@@ -135,14 +135,22 @@ export const zoomContainerMixin = (base) => class VictoryZoomContainer extends b
     };
   }
 
-  downsampleZoomData(props, childProps, domain) {
+  downsampleZoomData(props, child, domain) {
     const { downsample } = props;
-    const rawData = get(childProps, "data");
+
+    const getData = (childProps) => {
+      const { data, x, y } = childProps;
+      const defaultGetData = child.type && isFunction(child.type.getData) ?
+        child.type.getData : () => undefined;
+      // skip costly data formatting if x and y accessors are not present
+      return Array.isArray(data) && !x && !y ? data : defaultGetData(childProps);
+    };
+
+    const data = getData(child.props);
+
     // return undefined if downsample is not run, then default() will replace with child.props.data
-    if (!downsample || !rawData || !domain) { return undefined; }
+    if (!downsample || !domain || !data) { return undefined; }
 
-    // if data accessors are not used, skip calling expensive Data.formatData
-    const data = (childProps.x || childProps.y) ? Data.formatData(rawData, childProps) : rawData;
     const maxPoints = (downsample === true) ? DEFAULT_DOWNSAMPLE : downsample;
     const dimension = props.zoomDimension || "x";
 
@@ -195,7 +203,7 @@ export const zoomContainerMixin = (base) => class VictoryZoomContainer extends b
         defaults({
           domain: newDomain,
           data: role === "legend" ?
-            undefined : this.downsampleZoomData(props, currentChild.props, newDomain)
+            undefined : this.downsampleZoomData(props, currentChild, newDomain)
         }, currentChild.props)
       );
     });