feat: add clampValue with tests

src/helpers/adjust-out-of-range-value.ts

@@ -1,12 +1,11 @@
-export function adjustOutOfRangeValue(min: Date, max: Date, date: Date): Date {
-  const minTime = min.getTime();
-  const maxTime = max.getTime();
-  const currentTime = date.getTime();
-
-  let newValue = currentTime;
+import { clampValue } from './clamp-value.js';
 
-  if (currentTime < minTime) newValue = minTime;
-  if (currentTime > maxTime) newValue = maxTime;
-
-  return new Date(newValue);
+export function adjustOutOfRangeValue(min: Date, max: Date, date: Date): Date {
+  return new Date(
+    clampValue(
+      min.getTime(),
+      max.getTime(),
+      date.getTime()
+    )
+  );
 }

src/helpers/clamp-value.ts

@@ -0,0 +1,10 @@
+export function clampValue(
+  min: number,
+  max: number,
+  value: number
+): number {
+  return Math.min(
+    Math.max(min, value),
+    max
+  );
+}

src/tests/helpers/clamp-value.test.ts

@@ -0,0 +1,26 @@
+import { expect } from '@open-wc/testing';
+
+import { clampValue } from '../../helpers/clamp-value';
+import { messageFormatter } from '../test-utils/message-formatter';
+
+describe(clampValue.name, () => {
+  type A = [number, number, number, number];
+  const cases: A[] = [
+    [100, 300, 100, 100],
+    [100, 300, 200, 200],
+    [100, 300, 301, 300],
+    [100, 300, 99, 100],
+  ];
+  cases.forEach((a) => {
+    const [testMin, testMax, testValue, expected] = a;
+
+    it(
+      messageFormatter('clamps value (min=%s, max=%s, value=%s', a),
+      () => {
+        const result = clampValue(testMin, testMax, testValue);
+
+        expect(result).equal(expected);
+      }
+    )
+  });
+});

src/tests/helpers/dispatch-custom-event.test.ts

@@ -1,13 +1,12 @@
 import { expect } from '@open-wc/testing';
 
-import { dateValidator } from '../../helpers/date-validator';
 import { dispatchCustomEvent } from '../../helpers/dispatch-custom-event';
 import type { SupportedCustomEvent } from '../../typings';
 import { messageFormatter } from '../test-utils/message-formatter';
 
 type A = [SupportedCustomEvent['changed'] | undefined, SupportedCustomEvent['changed'] | null];
 
-describe(dateValidator.name, () => {
+describe(dispatchCustomEvent.name, () => {
   const cases: A[] = [
     [undefined, null],
     [

src/year-grid/to-next-selected-year.ts

@@ -1,3 +1,4 @@
+import { clampValue } from '../helpers/clamp-value.js';
 import { keyArrowDown, keyArrowLeft, keyArrowRight, keyArrowUp, keyEnd, keyHome } from '../key-values.js';
 import type { ToNextSelectableYearInit } from './typings.js';
 
@@ -32,8 +33,5 @@ export function toNextSelectedYear({
       return year;
   }
 
-  return Math.min(
-    Math.max(min.getUTCFullYear(), newYear),
-    max.getUTCFullYear()
-  );
+  return clampValue(min.getUTCFullYear(), max.getFullYear(), newYear);
 }