From f1ba3b6128c66f30e83c2514b9fd8ae2a4d77a6d Mon Sep 17 00:00:00 2001
From: Terkel Gjervig <terkel@terkel.com>
Date: Thu, 20 Oct 2016 21:00:18 -0700
Subject: [PATCH] feat: Added maxAdd and minSub

---
 src/math-toolbox.js  |  2 ++
 src/max-add.js       | 13 +++++++++++++
 src/min-sub.js       | 13 +++++++++++++
 test/max-add.test.js | 11 +++++++++++
 test/min-sub.test.js | 11 +++++++++++
 5 files changed, 50 insertions(+)
 create mode 100755 src/max-add.js
 create mode 100755 src/min-sub.js
 create mode 100644 test/max-add.test.js
 create mode 100644 test/min-sub.test.js

diff --git a/src/math-toolbox.js b/src/math-toolbox.js
index a33c1cb..ddf49fe 100755
--- a/src/math-toolbox.js
+++ b/src/math-toolbox.js
@@ -18,3 +18,5 @@ export { fuzzyCeil } from './fuzzy-ceil'
 export { fuzzyEqual } from './fuzzy-equal'
 export { fuzzyGreaterThan } from './fuzzy-greater-than'
 export { fuzzyLessThan } from './fuzzy-less-than'
+export { maxAdd } from './max-add'
+export { minSub } from './min-sub'
diff --git a/src/max-add.js b/src/max-add.js
new file mode 100755
index 0000000..1129d47
--- /dev/null
+++ b/src/max-add.js
@@ -0,0 +1,13 @@
+/**
+ * Adds the given amount to the value, but never lets the value go over the specified maximum.
+ *
+ * @param {number} value - The value to add the amount to.
+ * @param {number} amount - The amount to add to the value.
+ * @param {number} max - The maximum the value is allowed to be.
+ * @return {number} The new value.
+ */
+function maxAdd (value, amount, max) {
+  return Math.min(value + amount, max)
+}
+
+export { maxAdd }
diff --git a/src/min-sub.js b/src/min-sub.js
new file mode 100755
index 0000000..9b28710
--- /dev/null
+++ b/src/min-sub.js
@@ -0,0 +1,13 @@
+/**
+ * Subtracts the given amount from the value, but never lets the value go below the specified minimum.
+ *
+ * @param {number} value - The base value.
+ * @param {number} amount - The amount to subtract from the base value.
+ * @param {number} min - The minimum the value is allowed to be.
+ * @return {number} The new value.
+ */
+function minSub (value, amount, min) {
+  return Math.max(value - amount, min)
+}
+
+export { minSub }
diff --git a/test/max-add.test.js b/test/max-add.test.js
new file mode 100644
index 0000000..f2d3f43
--- /dev/null
+++ b/test/max-add.test.js
@@ -0,0 +1,11 @@
+import { maxAdd } from '../src/math-toolbox'
+
+describe('Adds the given amount to the value, but never lets the value go over the specified maximum', () => {
+  it('Add 10 to 30 with max 35, expect to it to return 35', () => {
+    expect(maxAdd(10, 30, 35)).toBe(35)
+  })
+
+  it('Add 10 to 30 with max 45, expect to it to return 40', () => {
+    expect(maxAdd(10, 30, 45)).toBe(40)
+  })
+})
diff --git a/test/min-sub.test.js b/test/min-sub.test.js
new file mode 100644
index 0000000..8e96bed
--- /dev/null
+++ b/test/min-sub.test.js
@@ -0,0 +1,11 @@
+import { minSub } from '../src/math-toolbox'
+
+describe('Subtracts the given amount from the value, but never lets the value go below the specified minimum', () => {
+  it('Substract 10 from 30 with min 25, expect to it to return 25', () => {
+    expect(minSub(10, 30, 25)).toBe(25)
+  })
+
+  it('Substract 10 from 30 with min 35, expect to it to return 35', () => {
+    expect(minSub(10, 30, 35)).toBe(35)
+  })
+})