Merge pull request #85 from elesueur/topic/elesueur/fixes-and-axis-ke…

…y-configs

Fix some ES6 syntax issue and add support for getting axis keys from options

README.md

@@ -38,6 +38,8 @@ To configure the trendline plugin you simply add a new config options to your da
 		colorMax: "green",
 		lineStyle: "dotted|solid",
 		width: 2,
+		xAxisKey: "time" (optional),
+		yAxisKey: "usage" (optional),
 		projection: true|false (optional)
 	}
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "chartjs-plugin-trendline",
-  "version": "2.0.5",
+  "version": "2.1.0",
   "description": "Trendline for Chart.js",
   "main": "src/chartjs-plugin-trendline.js",
   "scripts": {

src/chartjs-plugin-trendline.js

@@ -45,32 +45,37 @@ const pluginTrendlineLinear = {
     },
 };
 
-addFitter = (datasetMeta, ctx, dataset, xScale, yScale) => {
+const addFitter = (datasetMeta, ctx, dataset, xScale, yScale) => {
     let defaultColor = dataset.borderColor || 'rgba(169,169,169, .6)';
     let colorMin = dataset.trendlineLinear.colorMin || defaultColor;
     let colorMax = dataset.trendlineLinear.colorMax || defaultColor;
     let lineWidth = dataset.trendlineLinear.width || dataset.borderWidth;
     let lineStyle = dataset.trendlineLinear.lineStyle || 'solid';
     let fillColor = dataset.trendlineLinear.fillColor;
 
+    const parsing = typeof datasetMeta.controller.chart.options.parsing === "object" ?
+        datasetMeta.controller.chart.options.parsing : undefined;
+    const xAxisKey = dataset.trendlineLinear.xAxisKey || parsing ? parsing.xAxisKey : "x";
+    const yAxisKey = dataset.trendlineLinear.yAxisKey || parsing ? parsing.yAxisKey : "y";
+
     lineWidth = lineWidth !== undefined ? lineWidth : 3;
 
     let fitter = new LineFitter();
     let firstIndex = dataset.data.findIndex((d) => {
         return d !== undefined && d !== null;
     });
     let lastIndex = dataset.data.length - 1;
-    let startPos = datasetMeta.data[firstIndex].x;
-    let endPos = datasetMeta.data[lastIndex].x;
+    let startPos = datasetMeta.data[firstIndex][xAxisKey];
+    let endPos = datasetMeta.data[lastIndex][xAxisKey];
     let xy = typeof dataset.data[firstIndex] === 'object';
 
     dataset.data.forEach((data, index) => {
         if (data == null) return;
 
         if (['time', 'timeseries'].includes(xScale.options.type)) {
-            let x = data.x != null ? data.x : data.t;
+            let x = data[xAxisKey] != null ? data[xAxisKey] : data.t;
             if (x !== undefined) {
-                fitter.add(new Date(x).getTime(), data.y);
+                fitter.add(new Date(x).getTime(), data[yAxisKey]);
             } else {
                 fitter.add(index, data);
             }