fix problem caused by PR #248 - startAt set in future with interval

src/croner.js

@@ -500,14 +500,7 @@ Cron.prototype._next = function (prev) {
 
 	// If no previous run, and startAt and interval is set, calculate when the last run should have been
 	if (!prev && this.options.startAt && this.options.interval) {
-		prev = this.options.startAt;
-		const now = new CronDate(undefined, this.options.timezone || this.options.utcOffset);
-		let prevTimePlusInterval = prev.getTime() + this.options.interval * 1000;
-		while (prevTimePlusInterval <= now.getTime()) {
-			prev = new CronDate(prev, this.options.timezone || this.options.utcOffset).increment(this._states.pattern, this.options, true);
-			prevTimePlusInterval = prev.getTime() + this.options.interval * 1000;
-		}
-		hasPreviousRun = true;
+		[prev, hasPreviousRun] = this._calculatePreviousRun(prev, hasPreviousRun);
 	}
 
 	// Ensure previous run is a CronDate
@@ -540,6 +533,25 @@ Cron.prototype._next = function (prev) {
 		return nextRun;
 	}
 };
+/**
+ * Calculate the previous run if no previous run is supplied, but startAt and interval are set.
+ * This calculation is only necessary if the startAt time is before the current time.
+ * Should only be called from the _next function.
+ * @private
+ **/
+Cron.prototype._calculatePreviousRun = function (prev, hasPreviousRun) {
+	const now = new CronDate(undefined, this.options.timezone || this.options.utcOffset);
+	if (this.options.startAt.getTime() <= now.getTime()) {
+		prev = this.options.startAt;
+		let prevTimePlusInterval = prev.getTime() + this.options.interval * 1000;
+		while (prevTimePlusInterval <= now.getTime()) {
+			prev = new CronDate(prev, this.options.timezone || this.options.utcOffset).increment(this._states.pattern, this.options, true);
+			prevTimePlusInterval = prev.getTime() + this.options.interval * 1000;
+		}
+		hasPreviousRun = true;
+	}
+	return [prev, hasPreviousRun];
+};
 
 Cron.Cron = Cron;
 Cron.scheduledJobs = scheduledJobs;

test/node/js/src/suites/options.cjs

@@ -281,4 +281,22 @@ module.exports = function (Cron, test) {
 		assert.equal(nextRun.getSeconds(), sixDaysFromNow.getSeconds());
 	});
 
+	test("Valid interval starting in the future should give correct start date", function () {
+
+		const now = new Date();
+
+		const tomorrow = new Date(now);
+		tomorrow.setDate(now.getDate() + 1);
+		tomorrow.setHours(0, 31, 2);
+
+		const nextRun = Cron("* * * * * *", { interval: 60 * 60 * 24 * 7, startAt: tomorrow.toISOString() }).nextRun();
+
+		assert.equal(nextRun.getFullYear(), tomorrow.getFullYear());
+		assert.equal(nextRun.getMonth(), tomorrow.getMonth());
+		assert.equal(nextRun.getDate(), tomorrow.getDate());
+		assert.equal(nextRun.getHours(), tomorrow.getHours());
+		assert.equal(nextRun.getMinutes(), tomorrow.getMinutes());
+		// The seconds are not checked because there will be no previous run, so CronDate.increment() will add 1 second to the nextRun
+	});
+
 };

types/croner.d.cts

@@ -51,7 +51,7 @@ declare class Cron {
      */
     nextRuns(n: number, previous?: Date | string): Date[];
     /**
-     * Return the original pattern, it there was one
+     * Return the original pattern, if there was one
      *
      * @returns {string|undefined} - Original pattern
      */
@@ -138,6 +138,7 @@ declare class Cron {
     public trigger(): Promise<void>;
     private _checkTrigger;
     private _next;
+    private _calculatePreviousRun;
 }
 declare namespace Cron {
     export { Cron, scheduledJobs, TimePoint, CatchCallbackFn, ProtectCallbackFn, CronOptions, CronPatternPart, CronIndexOffset };

types/croner.d.ts

@@ -155,7 +155,7 @@ export class Cron {
      */
     nextRuns(n: number, previous?: Date | string): Date[];
     /**
-     * Return the original pattern, it there was one
+     * Return the original pattern, if there was one
      *
      * @returns {string|undefined} - Original pattern
      */
@@ -242,6 +242,7 @@ export class Cron {
     public trigger(): Promise<void>;
     private _checkTrigger;
     private _next;
+    private _calculatePreviousRun;
 }
 export namespace Cron {
     export { Cron };