Merge pull request #89 from studiometa/feature/math-clamp-utils

Add clamp math functions

Author: titouanmathis

src/utils/math/clamp.js

@@ -0,0 +1,22 @@
+/**
+ * Clamp a value in a given range.
+ * @param {number} value
+ * @param {number} min
+ * @param {number} max
+ * @return {number}
+ */
+export default function clamp(value, min, max) {
+  /* eslint-disable no-nested-ternary */
+  return min < max
+    ? value < min
+      ? min
+      : value > max
+      ? max
+      : value
+    : value < max
+    ? max
+    : value > min
+    ? min
+    : value;
+  /* eslint-enable no-nested-ternary */
+}

src/utils/math/clamp01.js

@@ -0,0 +1,10 @@
+import clamp from './clamp';
+
+/**
+ * Clamp a value in the 0–1 range.
+ * @param {number} value
+ * @return {number}
+ */
+export default function clamp01(value) {
+  return clamp(value, 0, 1);
+}

src/utils/math/index.js

@@ -1,6 +1,8 @@
+import clamp from './clamp';
+import clamp01 from './clamp01';
 import damp from './damp';
 import lerp from './lerp';
 import map from './map';
 import round from './round';
 
-export { damp, lerp, map, round };
+export { clamp, clamp01, damp, lerp, map, round };

tests/utils/math/clamp.spec.js

@@ -0,0 +1,13 @@
+import clamp from '~/utils/math/clamp';
+
+describe('clamp method', () => {
+  it('should clamp a value between the given range', () => {
+    expect(clamp(0, 0, 10)).toBe(0);
+    expect(clamp(-5, 0, 10)).toBe(0);
+    expect(clamp(15, 0, 10)).toBe(10);
+    expect(clamp(5, 0, 10)).toBe(5);
+    expect(clamp(5, 10, 0)).toBe(5);
+    expect(clamp(-5, 10, 0)).toBe(0);
+    expect(clamp(15, 10, 0)).toBe(10);
+  });
+});

tests/utils/math/clamp01.spec.js

@@ -0,0 +1,11 @@
+import clamp01 from '~/utils/math/clamp01';
+
+describe('clamp01 method', () => {
+  it('should clamp a value between 0 and 1', () => {
+    expect(clamp01(0)).toBe(0);
+    expect(clamp01(0.5)).toBe(0.5);
+    expect(clamp01(1)).toBe(1);
+    expect(clamp01(-1)).toBe(0);
+    expect(clamp01(2)).toBe(1);
+  });
+});

tests/utils/math/index.spec.js

@@ -2,6 +2,6 @@ import * as math from '~/utils/math';
 
 describe('~/utils/math exports', () => {
   it('should export all scripts', () => {
-    expect(Object.keys(math)).toEqual(['damp', 'lerp', 'map', 'round']);
+    expect(Object.keys(math)).toEqual(['clamp', 'clamp01', 'damp', 'lerp', 'map', 'round']);
   });
 });