fix(core): update

ts/smarttime.classes.cronjob.ts

@@ -0,0 +1,45 @@
+import * as plugins from './smarttime.plugins';
+import { CronManager } from './smarttime.classes.cronmanager';
+
+export type TJobFunction = (() => void) | (() => Promise<any>);
+
+export class CronJob {
+  public status: 'started' | 'stopped' | 'initial' = 'initial';
+  public cronExpression: string;
+  public jobFunction: TJobFunction;
+  
+  private cronInterval= plugins.cronParser.parseExpression('* * * * * *');
+  private nextExecutionUnix: number = 0;
+
+  constructor(cronManager: CronManager, cronExpressionArg: string, jobFunction: TJobFunction ) {
+    this.cronExpression = cronExpressionArg;
+    this.jobFunction = jobFunction;
+  }
+
+  /**
+   * checks wether the cronjob needs to be executed
+   */
+  public checkExecution() {
+    if (this.nextExecutionUnix === 0) {
+      this.nextExecutionUnix = this.cronInterval.next().toDate().getTime();
+      return;
+    }
+    if (Date.now() > this.nextExecutionUnix) {
+      this.jobFunction();
+      this.nextExecutionUnix = this.cronInterval.next().toDate().getTime();
+    }
+  }
+
+  public start() {
+    this.cronInterval = this.getCronInterval();
+    this.status = 'started';
+  }
+
+  public stop() {
+    this.status = 'stopped';
+  }
+
+  private getCronInterval () {
+    return plugins.cronParser.parseExpression(this.cronExpression);
+  }
+}