Efficiency improvements to chart old data pruning

Author: colinl

nodes/store/data.js

@@ -102,6 +102,22 @@ const setters = {
             }
             data[node.id].push(config.RED.util.cloneMessage(msg))
         }
+    },
+    /**
+     * Fast filtering of existing array data (skips cloning and save checks for fast data cleanup)
+     * @param {*} base - the base node
+     * @param {*} node - the owner node
+     * @param {(msg) => Boolean} filterFunction
+     */
+    filter (base, node, filterFunction) {
+        const currentData = data[node.id]
+        if (filterFunction && Array.isArray(currentData) && currentData.length) {
+            const filteredMessages = currentData.filter(filterFunction)
+            if (filteredMessages.length !== currentData.length) {
+                // no need for save operation to process messages - just apply them
+                data[node.id] = filteredMessages
+            }
+        }
     }
 }
 
@@ -111,5 +127,6 @@ module.exports = {
     setConfig: setters.setConfig,
     save: setters.save,
     append: setters.append,
+    filter: setters.filter,
     clear: setters.clear
 }

nodes/widgets/ui_chart.js

@@ -61,16 +61,16 @@ module.exports = function (RED) {
             if (removeOlder > 0) {
                 const removeOlderUnit = parseFloat(config.removeOlderUnit)
                 const ago = (removeOlder * removeOlderUnit) * 1000 // milliseconds ago
-                const cutoff = (new Date()).getTime() - ago
-                const _msg = datastore.get(node.id).filter((msg) => {
+                const cutOff = (new Date()).getTime() - ago
+                const filterFn = (msg) => {
                     let timestamp = msg._datapoint.x
                     // is x already a millisecond timestamp?
                     if (typeof (msg._datapoint.x) === 'string') {
                         timestamp = (new Date(msg._datapoint.x)).getTime()
                     }
-                    return timestamp > cutoff
-                })
-                datastore.save(base, node, _msg)
+                    return timestamp > cutOff
+                }
+                datastore.filter(base, node, filterFn)
             }
         }