feat(cron): added the support for json type schedule to cron api (#21340)

Added the support for JSON type schedule to cron API; previously it was string only.
fixes #21122

3 files changed, 197 insertions, 6 deletions

diff --git a/cli/tests/unit/cron_test.ts b/cli/tests/unit/cron_test.ts
index 79918ed2f..2a146bcfa 100644
--- a/cli/tests/unit/cron_test.ts
+++ b/cli/tests/unit/cron_test.ts
@@ -1,5 +1,9 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 import { assertEquals, assertThrows } from "./test_util.ts";
+import {
+  formatToCronSchedule,
+  parseScheduleToString,
+} from "../../../ext/cron/01_cron.ts";
 
 const sleep = (time: number) => new Promise((r) => setTimeout(r, time));
 
@@ -170,6 +174,31 @@ Deno.test(async function basicTest() {
   }
 });
 
+Deno.test(async function basicTestWithJsonFormatScheduleExpression() {
+  Deno.env.set("DENO_CRON_TEST_SCHEDULE_OFFSET", "100");
+
+  let count = 0;
+  const { promise, resolve } = Promise.withResolvers<void>();
+  const ac = new AbortController();
+  const c = Deno.cron(
+    "abc",
+    { minute: { every: 20 } },
+    { signal: ac.signal },
+    () => {
+      count++;
+      if (count > 5) {
+        resolve();
+      }
+    },
+  );
+  try {
+    await promise;
+  } finally {
+    ac.abort();
+    await c;
+  }
+});
+
 Deno.test(async function multipleCrons() {
   Deno.env.set("DENO_CRON_TEST_SCHEDULE_OFFSET", "100");
 
@@ -284,3 +313,67 @@ Deno.test(async function retriesWithBackoffScheduleOldApi() {
   // The cron should have executed 3 times (1st attempt and 2 retries).
   assertEquals(count, 3);
 });
+
+Deno.test("formatToCronSchedule - undefined value", () => {
+  const result = formatToCronSchedule();
+  assertEquals(result, "*");
+});
+
+Deno.test("formatToCronSchedule - number value", () => {
+  const result = formatToCronSchedule(5);
+  assertEquals(result, "5");
+});
+
+Deno.test("formatToCronSchedule - exact array value", () => {
+  const result = formatToCronSchedule({ exact: [1, 2, 3] });
+  assertEquals(result, "1,2,3");
+});
+
+Deno.test("formatToCronSchedule - exact number value", () => {
+  const result = formatToCronSchedule({ exact: 5 });
+  assertEquals(result, "5");
+});
+
+Deno.test("formatToCronSchedule - start, end, every values", () => {
+  const result = formatToCronSchedule({ start: 1, end: 10, every: 2 });
+  assertEquals(result, "1-10/2");
+});
+
+Deno.test("formatToCronSchedule - start, end values", () => {
+  const result = formatToCronSchedule({ start: 1, end: 10 });
+  assertEquals(result, "1-10");
+});
+
+Deno.test("formatToCronSchedule - start, every values", () => {
+  const result = formatToCronSchedule({ start: 1, every: 2 });
+  assertEquals(result, "1/2");
+});
+
+Deno.test("formatToCronSchedule - start value", () => {
+  const result = formatToCronSchedule({ start: 1 });
+  assertEquals(result, "1/1");
+});
+
+Deno.test("formatToCronSchedule - end, every values", () => {
+  assertThrows(
+    () => formatToCronSchedule({ end: 10, every: 2 }),
+    TypeError,
+    "Invalid cron schedule",
+  );
+});
+
+Deno.test("Parse CronSchedule to string", () => {
+  const result = parseScheduleToString({
+    minute: { exact: [1, 2, 3] },
+    hour: { start: 1, end: 10, every: 2 },
+    dayOfMonth: { exact: 5 },
+    month: { start: 1, end: 10 },
+    dayOfWeek: { start: 1, every: 2 },
+  });
+  assertEquals(result, "1,2,3 1-10/2 5 1-10 1/2");
+});
+
+Deno.test("Parse schedule to string - string", () => {
+  const result = parseScheduleToString("* * * * *");
+  assertEquals(result, "* * * * *");
+});
diff --git a/cli/tsc/dts/lib.deno.unstable.d.ts b/cli/tsc/dts/lib.deno.unstable.d.ts
index 5cba27a5e..895b7c0c5 100644
--- a/cli/tsc/dts/lib.deno.unstable.d.ts
+++ b/cli/tsc/dts/lib.deno.unstable.d.ts
@@ -1319,9 +1319,39 @@ declare namespace Deno {
 
   /** **UNSTABLE**: New API, yet to be vetted.
    *
+   * CronScheduleExpression is used as the type of `minute`, `hour`,
+   * `dayOfMonth`, `month`, and `dayOfWeek` in {@linkcode CronSchedule}.
+   * @category Cron
+   */
+  type CronScheduleExpression = number | { exact: number | number[] } | {
+    start?: number;
+    end?: number;
+    every?: number;
+  };
+
+  /** **UNSTABLE**: New API, yet to be vetted.
+   *
+   * CronSchedule is the interface used for JSON format
+   * cron `schedule`.
+   * @category Cron
+   */
+  export interface CronSchedule {
+    minute?: CronScheduleExpression;
+    hour?: CronScheduleExpression;
+    dayOfMonth?: CronScheduleExpression;
+    month?: CronScheduleExpression;
+    dayOfWeek?: CronScheduleExpression;
+  }
+
+  /** **UNSTABLE**: New API, yet to be vetted.
+   *
    * Create a cron job that will periodically execute the provided handler
    * callback based on the specified schedule.
    *
+   * `schedule` can be a string in the Unix cron format or in JSON format
+   * as specified by interface {@linkcode CronSchedule}, where time is specified
+   * using UTC time zone.
+   *
    * ```ts
    * Deno.cron("sample cron", "20 * * * *", () => {
    *   console.log("cron job executed");
@@ -1339,7 +1369,7 @@ declare namespace Deno {
    */
   export function cron(
     name: string,
-    schedule: string,
+    schedule: string | CronSchedule,
     handler: () => Promise<void> | void,
     options: { backoffSchedule?: number[]; signal?: AbortSignal },
   ): Promise<void>;
@@ -1355,14 +1385,15 @@ declare namespace Deno {
    * });
    * ```
    *
-   * `schedule` is a Unix cron format expression, where time is specified
+   * `schedule` can be a string in the Unix cron format or in JSON format
+   * as specified by interface {@linkcode CronSchedule}, where time is specified
    * using UTC time zone.
    *
    * @category Cron
    */
   export function cron(
     name: string,
-    schedule: string,
+    schedule: string | CronSchedule,
     handler: () => Promise<void> | void,
   ): Promise<void>;
 
@@ -1379,7 +1410,8 @@ declare namespace Deno {
    * });
    * ```
    *
-   * `schedule` is a Unix cron format expression, where time is specified
+   * `schedule` can be a string in the Unix cron format or in JSON format
+   * as specified by interface {@linkcode CronSchedule}, where time is specified
    * using UTC time zone.
    *
    * `backoffSchedule` option can be used to specify the retry policy for failed
@@ -1392,7 +1424,7 @@ declare namespace Deno {
    */
   export function cron(
     name: string,
-    schedule: string,
+    schedule: string | CronSchedule,
     options: { backoffSchedule?: number[]; signal?: AbortSignal },
     handler: () => Promise<void> | void,
   ): Promise<void>;
diff --git a/ext/cron/01_cron.ts b/ext/cron/01_cron.ts
index 30343905c..4a5250618 100644
--- a/ext/cron/01_cron.ts
+++ b/ext/cron/01_cron.ts
@@ -3,9 +3,73 @@
 // @ts-ignore internal api
 const core = Deno.core;
 
+export function formatToCronSchedule(
+  value?: number | { exact: number | number[] } | {
+    start?: number;
+    end?: number;
+    every?: number;
+  },
+): string {
+  if (value === undefined) {
+    return "*";
+  } else if (typeof value === "number") {
+    return value.toString();
+  } else {
+    const { exact } = value as { exact: number | number[] };
+    if (exact === undefined) {
+      const { start, end, every } = value as {
+        start?: number;
+        end?: number;
+        every?: number;
+      };
+      if (start !== undefined && end !== undefined && every !== undefined) {
+        return start + "-" + end + "/" + every;
+      } else if (start !== undefined && end !== undefined) {
+        return start + "-" + end;
+      } else if (start !== undefined && every !== undefined) {
+        return start + "/" + every;
+      } else if (start !== undefined) {
+        return start + "/1";
+      } else if (end === undefined && every !== undefined) {
+        return "*/" + every;
+      } else {
+        throw new TypeError("Invalid cron schedule");
+      }
+    } else {
+      if (typeof exact === "number") {
+        return exact.toString();
+      } else {
+        return exact.join(",");
+      }
+    }
+  }
+}
+
+export function parseScheduleToString(
+  schedule: string | Deno.CronSchedule,
+): string {
+  if (typeof schedule === "string") {
+    return schedule;
+  } else {
+    const {
+      minute,
+      hour,
+      dayOfMonth,
+      month,
+      dayOfWeek,
+    } = schedule;
+
+    return formatToCronSchedule(minute) +
+      " " + formatToCronSchedule(hour) +
+      " " + formatToCronSchedule(dayOfMonth) +
+      " " + formatToCronSchedule(month) +
+      " " + formatToCronSchedule(dayOfWeek);
+  }
+}
+
 function cron(
   name: string,
-  schedule: string,
+  schedule: string | Deno.CronSchedule,
   handlerOrOptions1:
     | (() => Promise<void> | void)
     | ({ backoffSchedule?: number[]; signal?: AbortSignal }),
@@ -20,6 +84,8 @@ function cron(
     throw new TypeError("Deno.cron requires a valid schedule");
   }
 
+  schedule = parseScheduleToString(schedule);
+
   let handler: () => Promise<void> | void;
   let options: { backoffSchedule?: number[]; signal?: AbortSignal } | undefined;