From d8a9a62335d15fd5d86ea727e71bad51ce0cb583 Mon Sep 17 00:00:00 2001
From: robonen <robonenandrew@gmail.com>
Date: Wed, 10 Apr 2024 20:21:44 +0700
Subject: [PATCH] feat(packages/stdlib): mapRange util

---
 packages/stdlib/src/math/index.ts             |  3 +-
 .../stdlib/src/math/mapRange/index.test.ts    | 46 +++++++++++++++++++
 packages/stdlib/src/math/mapRange/index.ts    | 18 ++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 packages/stdlib/src/math/mapRange/index.test.ts
 create mode 100644 packages/stdlib/src/math/mapRange/index.ts

diff --git a/packages/stdlib/src/math/index.ts b/packages/stdlib/src/math/index.ts
index 0244181..701b72a 100644
--- a/packages/stdlib/src/math/index.ts
+++ b/packages/stdlib/src/math/index.ts
@@ -1 +1,2 @@
-export * from './clamp';
\ No newline at end of file
+export * from './clamp';
+export * from './mapRange';
\ No newline at end of file
diff --git a/packages/stdlib/src/math/mapRange/index.test.ts b/packages/stdlib/src/math/mapRange/index.test.ts
new file mode 100644
index 0000000..55d362b
--- /dev/null
+++ b/packages/stdlib/src/math/mapRange/index.test.ts
@@ -0,0 +1,46 @@
+import { describe, expect, it } from 'vitest';
+import { mapRange } from './index';
+
+describe('mapRange', () => {
+    it('should map values from one range to another', () => {
+        // value at midpoint
+        expect(mapRange(5, 0, 10, 0, 100)).toBe(50);
+    
+        // value at min
+        expect(mapRange(0, 0, 10, 0, 100)).toBe(0);
+    
+        // value at max
+        expect(mapRange(10, 0, 10, 0, 100)).toBe(100);
+    
+        // value outside range (below)
+        expect(mapRange(-5, 0, 10, 0, 100)).toBe(0);
+    
+        // value outside range (above)
+        expect(mapRange(15, 0, 10, 0, 100)).toBe(100);
+    
+        // value at midpoint of negative range
+        expect(mapRange(75, 50, 100, -50, 50)).toBe(0);
+    
+        // value at midpoint of negative range
+        expect(mapRange(-25, -50, 0, 0, 100)).toBe(50);
+      });
+    
+      it('should handle floating-point numbers correctly', () => {
+        // floating-point value
+        expect(mapRange(3.5, 0, 10, 0, 100)).toBe(35);
+    
+        // positive floating-point ranges
+        expect(mapRange(1.25, 0, 2.5, 0, 100)).toBe(50);
+    
+        // negative floating-point value
+        expect(mapRange(-2.5, -5, 0, 0, 100)).toBe(50);
+
+        // negative floating-point ranges
+        expect(mapRange(-1.25, -2.5, 0, 0, 100)).toBe(50);
+      });
+    
+      it('should handle edge cases', () => {
+        // input range is zero (should return output min)
+        expect(mapRange(5, 0, 0, 0, 100)).toBe(0);
+      });
+});
\ No newline at end of file
diff --git a/packages/stdlib/src/math/mapRange/index.ts b/packages/stdlib/src/math/mapRange/index.ts
new file mode 100644
index 0000000..cc9cddf
--- /dev/null
+++ b/packages/stdlib/src/math/mapRange/index.ts
@@ -0,0 +1,18 @@
+import { clamp } from "../clamp";
+
+/**
+ * Map a value from one range to another
+ * 
+ * @param {number} value The value to map
+ * @param {number} in_min The minimum value of the input range
+ * @param {number} in_max The maximum value of the input range
+ * @param {number} out_min The minimum value of the output range
+ * @param {number} out_max The maximum value of the output range
+ * @returns {number} The mapped value
+ */
+export function mapRange(value: number, in_min: number, in_max: number, out_min: number, out_max: number): number {
+  if (in_min === in_max)
+    return out_min;
+  
+  return (clamp(value, in_min, in_max) - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+}
\ No newline at end of file