From b43566898ce6eab18ed8d8c36d44e4dbeb7624d5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Benjamin=20Strau=C3=9F?= <b.strauss@netzbewegung.com>
Date: Tue, 16 Jan 2018 14:51:38 +0100
Subject: [PATCH] feat(math): mapRange

---
 src/math/math.js       | 17 +++++++++++++++++
 test/math/math_spec.js | 22 ++++++++++++++++++++++
 test/test_main.js      |  2 ++
 3 files changed, 41 insertions(+)
 create mode 100644 src/math/math.js
 create mode 100644 test/math/math_spec.js

diff --git a/src/math/math.js b/src/math/math.js
new file mode 100644
index 0000000..eacbba0
--- /dev/null
+++ b/src/math/math.js
@@ -0,0 +1,17 @@
+goog.module('clulib.math');
+
+/**
+ * Maps a value from one range to another range.
+ *
+ * @param {number} x
+ * @param {number} inMin
+ * @param {number} inMax
+ * @param {number} outMin
+ * @param {number} outMax
+ * @returns {number}
+ */
+function mapRange (x, inMin, inMax, outMin, outMax) {
+  return (x - inMin) * (outMax - outMin) / (inMax - inMin) + outMin;
+}
+
+exports = {mapRange};
diff --git a/test/math/math_spec.js b/test/math/math_spec.js
new file mode 100644
index 0000000..796f9da
--- /dev/null
+++ b/test/math/math_spec.js
@@ -0,0 +1,22 @@
+goog.module('test.clulib.math');
+
+const {mapRange} = goog.require('clulib.math');
+
+exports = function () {
+  describe('clulib.math', () => {
+    describe('mapRange', () => {
+      it('should map a value from one range to another range', () => {
+        expect(mapRange(1, 0, 10, 0, 100)).toBe(10);
+        expect(mapRange(5, 0, 10, 0, 100)).toBe(50);
+
+        expect(mapRange(11, 0, 10, 0, 100)).toBe(110);
+        expect(mapRange(15, 0, 10, 0, 100)).toBe(150);
+
+        expect(mapRange(-1, 0, 10, 0, 100)).toBe(-10);
+        expect(mapRange(-5, 0, 10, 0, 100)).toBe(-50);
+
+        expect(mapRange(-5, -10, 0, -100, 0)).toBe(-50);
+      });
+    });
+  });
+};
diff --git a/test/test_main.js b/test/test_main.js
index 821cb97..0375477 100644
--- a/test/test_main.js
+++ b/test/test_main.js
@@ -6,6 +6,7 @@ const cmMain = goog.require('test.clulib.cm');
 const domMain = goog.require('test.clulib.dom');
 const functionsMain = goog.require('test.clulib.functions');
 const httpRequestMain = goog.require('test.clulib.net.http_request');
+const mathMain = goog.require('test.clulib.math');
 
 arrayMain();
 asyncCompleterMain();
@@ -13,3 +14,4 @@ cmMain();
 domMain();
 functionsMain();
 httpRequestMain();
+mathMain();