feat(#477): add isHoliday function (#478)

* feat(#477): add isHoliday function

* docs(#477): include utils section

README.md

@@ -72,6 +72,22 @@ If the year is omitted, by default the function will return the holidays for the
 const currentYearHolidays = colombianHolidays();
 ```
 
+## Utils
+
+The package provides the `isHoliday` helper which can be imported from `lib/utils`:
+
+```js
+import { isHoliday } from 'colombian-holidays/lib/utils`
+
+const date = new Date("2018-01-01T05:00:00.000Z")
+
+if (isHoliday(date)) {
+  console.log('it is holiday');
+} else {
+  console.log('it is not');
+}
+```
+
 ### TypeScript
 
 The module is written in TypeScript and type definitions files are included.

src/utils.test.ts

@@ -0,0 +1,10 @@
+import { isHoliday } from "./utils";
+
+describe("test isHoliday", () => {
+  it(`should return true for a holiday date object`, () => {
+    expect(isHoliday(new Date("2018-01-01T05:00:00.000Z"))).toBe(true);
+  });
+  it(`should return false for a non holiday date object`, () => {
+    expect(isHoliday(new Date("2018-01-02T05:00:00.000Z"))).toBe(false);
+  });
+});

src/utils.ts

@@ -0,0 +1,14 @@
+import colombianHolidays from ".";
+
+export function isHoliday(date: Date): boolean {
+  return colombianHolidays(date.getUTCFullYear()).some(
+    ({ celebrationDate }) => {
+      const d = new Date(celebrationDate);
+      return (
+        d.getUTCDate() === date.getUTCDate() &&
+        d.getUTCMonth() === date.getUTCMonth() &&
+        d.getUTCFullYear() === date.getUTCFullYear()
+      );
+    }
+  );
+}