feat(std/datetime): add is leap and difference functions (#4857)

2 files changed, 249 insertions, 67 deletions

diff --git a/std/datetime/mod.ts b/std/datetime/mod.ts
index 7503eccb4..99332e046 100644
--- a/std/datetime/mod.ts
+++ b/std/datetime/mod.ts
@@ -3,6 +3,12 @@ import { assert } from "../_util/assert.ts";
 
 export type DateFormat = "mm-dd-yyyy" | "dd-mm-yyyy" | "yyyy-mm-dd";
 
+export const SECOND = 1e3;
+export const MINUTE = SECOND * 60;
+export const HOUR = MINUTE * 60;
+export const DAY = HOUR * 24;
+export const WEEK = DAY * 7;
+
 function execForce(reg: RegExp, pat: string): RegExpExecArray {
   const v = reg.exec(pat);
   assert(v != null);
@@ -96,13 +102,12 @@ export function parseDateTime(
  * @return Number of the day in year
  */
 export function dayOfYear(date: Date): number {
-  const dayMs = 1000 * 60 * 60 * 24;
   const yearStart = new Date(date.getFullYear(), 0, 0);
   const diff =
     date.getTime() -
     yearStart.getTime() +
     (yearStart.getTimezoneOffset() - date.getTimezoneOffset()) * 60 * 1000;
-  return Math.floor(diff / dayMs);
+  return Math.floor(diff / DAY);
 }
 
 /**
@@ -150,3 +155,128 @@ export function toIMF(date: Date): string {
     months[date.getUTCMonth()]
   } ${y} ${h}:${min}:${s} GMT`;
 }
+
+/**
+ * Check given year is a leap year or not.
+ * based on : https://docs.microsoft.com/en-us/office/troubleshoot/excel/determine-a-leap-year
+ * @param year year in number or Date format
+ */
+export function isLeap(year: Date | number): boolean {
+  const yearNumber = year instanceof Date ? year.getFullYear() : year;
+  return (
+    (yearNumber % 4 === 0 && yearNumber % 100 !== 0) || yearNumber % 400 === 0
+  );
+}
+
+export type Unit =
+  | "miliseconds"
+  | "seconds"
+  | "minutes"
+  | "hours"
+  | "days"
+  | "weeks"
+  | "months"
+  | "quarters"
+  | "years";
+
+export type DifferenceFormat = Partial<Record<Unit, number>>;
+
+export type DifferenceOptions = {
+  units?: Unit[];
+};
+
+/**
+ * Calculate difference between two dates.
+ * @param from Year to calculate difference
+ * @param to Year to calculate difference with
+ * @param options Options for determining how to respond
+ *
+ * example :
+ *
+ * ```typescript
+ * datetime.difference(new Date("2020/1/1"),new Date("2020/2/2"),{ units : ["days","months"] })
+ * ```
+ */
+export function difference(
+  from: Date,
+  to: Date,
+  options?: DifferenceOptions
+): DifferenceFormat {
+  const uniqueUnits = options?.units
+    ? [...new Set(options?.units)]
+    : [
+        "miliseconds",
+        "seconds",
+        "minutes",
+        "hours",
+        "days",
+        "weeks",
+        "months",
+        "quarters",
+        "years",
+      ];
+
+  const bigger = Math.max(from.getTime(), to.getTime());
+  const smaller = Math.min(from.getTime(), to.getTime());
+  const differenceInMs = bigger - smaller;
+
+  const differences: DifferenceFormat = {};
+
+  for (const uniqueUnit of uniqueUnits) {
+    switch (uniqueUnit) {
+      case "miliseconds":
+        differences.miliseconds = differenceInMs;
+        break;
+      case "seconds":
+        differences.seconds = Math.floor(differenceInMs / SECOND);
+        break;
+      case "minutes":
+        differences.minutes = Math.floor(differenceInMs / MINUTE);
+        break;
+      case "hours":
+        differences.hours = Math.floor(differenceInMs / HOUR);
+        break;
+      case "days":
+        differences.days = Math.floor(differenceInMs / DAY);
+        break;
+      case "weeks":
+        differences.weeks = Math.floor(differenceInMs / WEEK);
+        break;
+      case "months":
+        differences.months = calculateMonthsDifference(bigger, smaller);
+        break;
+      case "quarters":
+        differences.quarters = Math.floor(
+          (typeof differences.months !== "undefined" &&
+            differences.months / 4) ||
+            calculateMonthsDifference(bigger, smaller) / 4
+        );
+        break;
+      case "years":
+        differences.years = Math.floor(
+          (typeof differences.months !== "undefined" &&
+            differences.months / 12) ||
+            calculateMonthsDifference(bigger, smaller) / 12
+        );
+        break;
+    }
+  }
+
+  return differences;
+}
+
+function calculateMonthsDifference(bigger: number, smaller: number): number {
+  const biggerDate = new Date(bigger);
+  const smallerDate = new Date(smaller);
+  const yearsDiff = biggerDate.getFullYear() - smallerDate.getFullYear();
+  const monthsDiff = biggerDate.getMonth() - smallerDate.getMonth();
+  const calendarDiffrences = Math.abs(yearsDiff * 12 + monthsDiff);
+  const compareResult = biggerDate > smallerDate ? 1 : -1;
+  biggerDate.setMonth(
+    biggerDate.getMonth() - compareResult * calendarDiffrences
+  );
+  const isLastMonthNotFull =
+    biggerDate > smallerDate ? 1 : -1 === -compareResult ? 1 : 0;
+  const months = compareResult * (calendarDiffrences - isLastMonthNotFull);
+  return months === 0 ? 0 : months;
+}
diff --git a/std/datetime/test.ts b/std/datetime/test.ts
index c50914342..dc4c7278e 100644
--- a/std/datetime/test.ts
+++ b/std/datetime/test.ts
@@ -1,83 +1,101 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { assertEquals, assertThrows } from "../testing/asserts.ts";
+import { assert, assertEquals, assertThrows } from "../testing/asserts.ts";
 import * as datetime from "./mod.ts";
 
-Deno.test("parseDateTime", function (): void {
-  assertEquals(
-    datetime.parseDateTime("01-03-2019 16:30", "mm-dd-yyyy hh:mm"),
-    new Date(2019, 0, 3, 16, 30)
-  );
-  assertEquals(
-    datetime.parseDateTime("03-01-2019 16:31", "dd-mm-yyyy hh:mm"),
-    new Date(2019, 0, 3, 16, 31)
-  );
-  assertEquals(
-    datetime.parseDateTime("2019-01-03 16:32", "yyyy-mm-dd hh:mm"),
-    new Date(2019, 0, 3, 16, 32)
-  );
-  assertEquals(
-    datetime.parseDateTime("16:33 01-03-2019", "hh:mm mm-dd-yyyy"),
-    new Date(2019, 0, 3, 16, 33)
-  );
-  assertEquals(
-    datetime.parseDateTime("16:34 03-01-2019", "hh:mm dd-mm-yyyy"),
-    new Date(2019, 0, 3, 16, 34)
-  );
-  assertEquals(
-    datetime.parseDateTime("16:35 2019-01-03", "hh:mm yyyy-mm-dd"),
-    new Date(2019, 0, 3, 16, 35)
-  );
+Deno.test({
+  name: "[std/datetime] parseDate",
+  fn: () => {
+    assertEquals(
+      datetime.parseDateTime("01-03-2019 16:30", "mm-dd-yyyy hh:mm"),
+      new Date(2019, 0, 3, 16, 30)
+    );
+    assertEquals(
+      datetime.parseDateTime("03-01-2019 16:31", "dd-mm-yyyy hh:mm"),
+      new Date(2019, 0, 3, 16, 31)
+    );
+    assertEquals(
+      datetime.parseDateTime("2019-01-03 16:32", "yyyy-mm-dd hh:mm"),
+      new Date(2019, 0, 3, 16, 32)
+    );
+    assertEquals(
+      datetime.parseDateTime("16:33 01-03-2019", "hh:mm mm-dd-yyyy"),
+      new Date(2019, 0, 3, 16, 33)
+    );
+    assertEquals(
+      datetime.parseDateTime("16:34 03-01-2019", "hh:mm dd-mm-yyyy"),
+      new Date(2019, 0, 3, 16, 34)
+    );
+    assertEquals(
+      datetime.parseDateTime("16:35 2019-01-03", "hh:mm yyyy-mm-dd"),
+      new Date(2019, 0, 3, 16, 35)
+    );
+  },
 });
 
-Deno.test("invalidParseDateTimeFormatThrows", function (): void {
-  assertThrows(
-    (): void => {
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      (datetime as any).parseDateTime("2019-01-01 00:00", "x-y-z");
-    },
-    Error,
-    "Invalid datetime format!"
-  );
+Deno.test({
+  name: "[std/datetime] invalidParseDateTimeFormatThrows",
+  fn: () => {
+    assertThrows(
+      (): void => {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (datetime as any).parseDateTime("2019-01-01 00:00", "x-y-z");
+      },
+      Error,
+      "Invalid datetime format!"
+    );
+  },
 });
 
-Deno.test("parseDate", function (): void {
-  assertEquals(
-    datetime.parseDate("01-03-2019", "mm-dd-yyyy"),
-    new Date(2019, 0, 3)
-  );
-  assertEquals(
-    datetime.parseDate("03-01-2019", "dd-mm-yyyy"),
-    new Date(2019, 0, 3)
-  );
-  assertEquals(
-    datetime.parseDate("2019-01-03", "yyyy-mm-dd"),
-    new Date(2019, 0, 3)
-  );
+Deno.test({
+  name: "[std/datetime] parseDate",
+  fn: () => {
+    assertEquals(
+      datetime.parseDate("01-03-2019", "mm-dd-yyyy"),
+      new Date(2019, 0, 3)
+    );
+    assertEquals(
+      datetime.parseDate("03-01-2019", "dd-mm-yyyy"),
+      new Date(2019, 0, 3)
+    );
+    assertEquals(
+      datetime.parseDate("2019-01-03", "yyyy-mm-dd"),
+      new Date(2019, 0, 3)
+    );
+  },
 });
 
-Deno.test("invalidParseDateFormatThrows", function (): void {
-  assertThrows(
-    (): void => {
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      (datetime as any).parseDate("2019-01-01", "x-y-z");
-    },
-    Error,
-    "Invalid date format!"
-  );
+Deno.test({
+  name: "[std/datetime] invalidParseDateFormatThrows",
+  fn: () => {
+    assertThrows(
+      (): void => {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (datetime as any).parseDate("2019-01-01", "x-y-z");
+      },
+      Error,
+      "Invalid date format!"
+    );
+  },
 });
 
-Deno.test("DayOfYear", function (): void {
-  assertEquals(1, datetime.dayOfYear(new Date("2019-01-01T03:24:00")));
-  assertEquals(70, datetime.dayOfYear(new Date("2019-03-11T03:24:00")));
-  assertEquals(365, datetime.dayOfYear(new Date("2019-12-31T03:24:00")));
+Deno.test({
+  name: "[std/datetime] DayOfYear",
+  fn: () => {
+    assertEquals(1, datetime.dayOfYear(new Date("2019-01-01T03:24:00")));
+    assertEquals(70, datetime.dayOfYear(new Date("2019-03-11T03:24:00")));
+    assertEquals(365, datetime.dayOfYear(new Date("2019-12-31T03:24:00")));
+  },
 });
 
-Deno.test("currentDayOfYear", function (): void {
-  assertEquals(datetime.currentDayOfYear(), datetime.dayOfYear(new Date()));
+Deno.test({
+  name: "[std/datetime] currentDayOfYear",
+  fn: () => {
+    assertEquals(datetime.currentDayOfYear(), datetime.dayOfYear(new Date()));
+  },
 });
 
 Deno.test({
-  name: "[DateTime] to IMF",
+  name: "[std/datetime] to IMF",
   fn(): void {
     const actual = datetime.toIMF(new Date(Date.UTC(1994, 3, 5, 15, 32)));
     const expected = "Tue, 05 Apr 1994 15:32:00 GMT";
@@ -86,10 +104,44 @@ Deno.test({
 });
 
 Deno.test({
-  name: "[DateTime] to IMF 0",
+  name: "[std/datetime] to IMF 0",
   fn(): void {
     const actual = datetime.toIMF(new Date(0));
     const expected = "Thu, 01 Jan 1970 00:00:00 GMT";
     assertEquals(actual, expected);
   },
 });
+
+Deno.test({
+  name: "[std/datetime] isLeap",
+  fn(): void {
+    assert(datetime.isLeap(1992));
+    assert(datetime.isLeap(2000));
+    assert(!datetime.isLeap(2003));
+    assert(!datetime.isLeap(2007));
+  },
+});
+
+Deno.test({
+  name: "[std/datetime] Difference",
+  fn(): void {
+    const denoInit = new Date("2018/5/14");
+    const denoRelaseV1 = new Date("2020/5/13");
+    let difference = datetime.difference(denoRelaseV1, denoInit, {
+      units: ["days", "months", "years"],
+    });
+    assertEquals(difference.days, 730);
+    assertEquals(difference.months, 23);
+    assertEquals(difference.years, 1);
+
+    const birth = new Date("1998/2/23 10:10:10");
+    const old = new Date("1998/2/23 11:11:11");
+    difference = datetime.difference(birth, old, {
+      units: ["miliseconds", "minutes", "seconds", "hours"],
+    });
+    assertEquals(difference.miliseconds, 3661000);
+    assertEquals(difference.seconds, 3661);
+    assertEquals(difference.minutes, 61);
+    assertEquals(difference.hours, 1);
+  },
+});