From eddef78b794c62a1a257a742237634fab2648511 Mon Sep 17 00:00:00 2001
From: Noah Loomans <noahloomans@gmail.com>
Date: Tue, 3 Jul 2018 20:51:14 +0200
Subject: client: Add withinRange
---
src/client/react/lib/withinRange.js | 11 +++++++++++
src/client/react/lib/withinRange.test.js | 18 ++++++++++++++++++
2 files changed, 29 insertions(+)
create mode 100644 src/client/react/lib/withinRange.js
create mode 100644 src/client/react/lib/withinRange.test.js
(limited to 'src')
diff --git a/src/client/react/lib/withinRange.js b/src/client/react/lib/withinRange.js
new file mode 100644
index 0000000..d3d4f24
--- /dev/null
+++ b/src/client/react/lib/withinRange.js
@@ -0,0 +1,11 @@
+export default function withinRange(number, rangeMax) {
+ if (number < 0) {
+ return withinRange(number + (rangeMax + 1), rangeMax);
+ }
+
+ if (number > rangeMax) {
+ return withinRange(number - (rangeMax + 1), rangeMax);
+ }
+
+ return number;
+}
diff --git a/src/client/react/lib/withinRange.test.js b/src/client/react/lib/withinRange.test.js
new file mode 100644
index 0000000..baec122
--- /dev/null
+++ b/src/client/react/lib/withinRange.test.js
@@ -0,0 +1,18 @@
+import withinRange from './withinRange';
+
+describe('withinRange', () => {
+ describe('the number is within range', () => {
+ it('just returns the number', () => {
+ expect(withinRange(5, 7)).toEqual(5);
+ });
+ });
+
+ describe('the number is outside the range', () => {
+ it('wraps the number until within range', () => {
+ expect(withinRange(-1, 6)).toEqual(6);
+ expect(withinRange(7, 6)).toEqual(0);
+ expect(withinRange(-20, 6)).toEqual(1);
+ expect(withinRange(20, 6)).toEqual(6);
+ });
+ });
+});
--
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