Fix time series scale to have each data point is spread equidistant (#11388)

* Fix time series scale to have each data point is spread equidistant

* remove tabs

* remove casting and add/update test cases

Author: stockiNail

src/scales/scale.time.js

@@ -445,7 +445,7 @@ export default class TimeScale extends Scale {
 	 * `minor` unit using the given scale time `options`.
 	 * Important: this method can return ticks outside the min and max range, it's the
 	 * responsibility of the calling code to clamp values if needed.
-	 * @private
+	 * @protected
 	 */
   _generate() {
     const adapter = this._adapter;
@@ -485,7 +485,7 @@ export default class TimeScale extends Scale {
     }
 
     // @ts-ignore
-    return Object.keys(ticks).sort((a, b) => a - b).map(x => +x);
+    return Object.keys(ticks).sort(sorter).map(x => +x);
   }
 
   /**

src/scales/scale.timeseries.js

@@ -110,6 +110,25 @@ class TimeSeriesScale extends TimeScale {
     return table;
   }
 
+  /**
+    * Generates all timestamps defined in the data.
+    * Important: this method can return ticks outside the min and max range, it's the
+    * responsibility of the calling code to clamp values if needed.
+    * @protected
+    */
+  _generate() {
+    const min = this.min;
+    const max = this.max;
+    let timestamps = super.getDataTimestamps();
+    if (!timestamps.includes(min) || !timestamps.length) {
+      timestamps.splice(0, 0, min);
+    }
+    if (!timestamps.includes(max) || timestamps.length === 1) {
+      timestamps.push(max);
+    }
+    return timestamps.sort((a, b) => a - b);
+  }
+
   /**
 	 * Returns all timestamps
 	 * @return {number[]}

test/fixtures/scale.timeseries/data-timestamps.js

@@ -0,0 +1,46 @@
+module.exports = {
+  threshold: 0.01,
+  tolerance: 0.0015,
+  config: {
+    type: 'line',
+    data: {
+      datasets: [{data: [
+        {x: 1687849697000, y: 904},
+        {x: 1687817063000, y: 905},
+        {x: 1687694268000, y: 913},
+        {x: 1687609438000, y: 914},
+        {x: 1687561387000, y: 916},
+        {x: 1686875127000, y: 918},
+        {x: 1686873138000, y: 920},
+        {x: 1686872777000, y: 928},
+        {x: 1686081641000, y: 915}
+      ], fill: false}, {data: [
+        {x: 1687816803000, y: 1105},
+        {x: 1686869490000, y: 1114},
+        {x: 1686869397000, y: 1103},
+        {x: 1686869225000, y: 1091},
+        {x: 1686556516000, y: 1078}
+      ]}]
+    },
+    options: {
+      scales: {
+        x: {
+          type: 'timeseries',
+          bounds: 'data',
+          time: {
+            unit: 'day'
+          },
+          ticks: {
+            source: 'auto'
+          }
+        },
+        y: {
+          display: false
+        }
+      }
+    }
+  },
+  options: {
+    spriteText: true
+  }
+};