Update:Remove node-cron dependency

server/libs/nodeCron/scheduler.js

@@ -0,0 +1,49 @@
+'use strict';
+
+const EventEmitter = require('events');
+const TimeMatcher = require('./time-matcher');
+
+class Scheduler extends EventEmitter{
+    constructor(pattern, timezone, autorecover){
+        super();
+        this.timeMatcher = new TimeMatcher(pattern, timezone);
+        this.autorecover = autorecover;
+    }
+
+    start(){
+        // clear timeout if exists
+        this.stop();
+
+        let lastCheck = process.hrtime();
+        let lastExecution = this.timeMatcher.apply(new Date());
+
+        const matchTime = () => {
+            const delay = 1000;
+            const elapsedTime = process.hrtime(lastCheck);
+            const elapsedMs = (elapsedTime[0] * 1e9 + elapsedTime[1]) / 1e6;
+            const missedExecutions = Math.floor(elapsedMs / 1000);
+            
+            for(let i = missedExecutions; i >= 0; i--){
+                const date = new Date(new Date().getTime() - i * 1000);
+                let date_tmp = this.timeMatcher.apply(date);
+                if(lastExecution.getTime() < date_tmp.getTime() && (i === 0 || this.autorecover) && this.timeMatcher.match(date)){
+                    this.emit('scheduled-time-matched', date_tmp);
+                    date_tmp.setMilliseconds(0);
+                    lastExecution = date_tmp;
+                }
+            }
+            lastCheck = process.hrtime();
+            this.timeout = setTimeout(matchTime, delay);
+        };
+        matchTime();
+    }
+
+    stop(){
+        if(this.timeout){
+            clearTimeout(this.timeout);
+        }
+        this.timeout = null;
+    }
+}
+
+module.exports = Scheduler;