add weight causes updating old chart instead of creating new chart, closes #53

src/scripts/weight.html

@@ -19,6 +19,7 @@
     (async function() {
         const dateEl = $("#weight-date");
         const weightEl = $("#weight");
+        let chart;
 
         dateEl.datepicker();
         dateEl.datepicker('option', 'dateFormat', 'yy-mm-dd');
@@ -49,10 +50,24 @@
 
             showMessage("Weight has been saved");
 
-        drawChart();
+            const data = await getData();
+
+            chart.data = data;
+            chart.update();
         }
 
         async function drawChart() {
+            const data = await getData();
+
+            const ctx = $("#canvas")[0].getContext("2d");
+
+            chart = new Chart(ctx, {
+                type: 'line',
+                data: data
+            });
+        }
+
+        async function getData() {
             const data = await server.exec([], async () => {
                 const notes = await this.getNotesWithAttribute('date_data');
                 const data = [];
@@ -71,21 +86,20 @@
                 return data;
             });
 
-        const ctx = $("#canvas")[0].getContext("2d");
-
-        new Chart(ctx, {
-            type: 'line',
-            data: {
-                labels: data.map(row => row.date),
-                datasets: [{
+            const datasets = [{
                 label: "Weight",
                 backgroundColor: 'red',
                 borderColor: 'red',
                 data: data.map(row => row.weight),
                 fill: false
-                }]
-            }
-        });
+            }];
+
+            const labels = data.map(row => row.date);
+
+            return {
+                labels: labels,
+                datasets: datasets
+            };
         }
 
         $("#weight-form").submit(event => {

src/services/attributes.js

@@ -53,6 +53,10 @@ async function getNoteIdsWithAttribute(name) {
 }
 
 async function createAttribute(noteId, name, value = "", sourceId = null) {
+    if (value === null || value === undefined) {
+        value = "";
+    }
+
     const now = utils.nowDate();
     const attributeId = utils.newAttributeId();