Fix: #124. Ghosting when the gap is caused by other strings (e.g unknown)

Fix ghosting created by "unknown" values
Remove converting unavailable to null, as plotly still interprets the axis as numerical

Author: dbuezas

src/plotly-graph-card.ts

@@ -29,14 +29,15 @@ import { parseTimeDuration } from "./duration/duration";
 
 const componentName = isProduction ? "plotly-graph" : "plotly-graph-dev";
 
-const isDefined = (y: any) => y !== null && y !== undefined;
+const isNumber = (y: any) => !Number.isNaN(parseFloat(y));
 
 function patchLonelyDatapoints(xs: Datum[], ys: Datum[]) {
-  /* Ghost traces when data has single non-unavailable states sandwiched between unavailable ones
+  /* Ghost traces when data has single numeric value sandwiched between unavailable, unknown, etc ones
      see: https://github.com/dbuezas/lovelace-plotly-graph-card/issues/103
+     and: https://github.com/dbuezas/lovelace-plotly-graph-card/issues/124
   */
   for (let i = 0; i < xs.length; i++) {
-    if (!isDefined(ys[i - 1]) && isDefined(ys[i]) && !isDefined(ys[i + 1])) {
+    if (!isNumber(ys[i - 1]) && isNumber(ys[i]) && !isNumber(ys[i + 1])) {
       ys.splice(i, 0, ys[i]);
       xs.splice(i, 0, xs[i]);
     }
@@ -567,9 +568,7 @@ export class PlotlyGraph extends HTMLElement {
       if (isEntityIdAttrConfig(trace)) name += ` (${trace.attribute}) `;
       if (isEntityIdStatisticsConfig(trace)) name += ` (${trace.statistic}) `;
       const xsIn = history.map(({ timestamp }) => new Date(timestamp));
-      const ysIn: Datum[] = history.map(({ value }) =>
-        value === "unavailable" ? null : value
-      );
+      const ysIn: Datum[] = history.map(({ value }) => value);
 
       let xs: Datum[] = xsIn;
       let ys = ysIn;