feat: within

Author: terkelg

README.md

@@ -75,6 +75,7 @@ https://unpkg.com/math-toolbox/dist/math-toolbox.umd.min.js
 | isOdd | Returns true if the number given is odd. |
 | isEven | Returns true if the number given is even. |
 | difference | Returns the absolute difference between two values. |
+| within | Checks if two values are within the given tolerance of each other |
 
 ## Plans
 See GitHub Wiki:

docs/index.html

@@ -293,6 +293,16 @@ <h3 class='mb0 no-anchor'></h3>
 
                 </li>
 
+                
+                <li><a
+                  href='#within'
+                  class="">
+                  within
+                  
+                </a>
+                
+                </li>
+              
             </ul>
           </div>
           <div class='mt1 h6 quiet'>
@@ -2371,6 +2381,87 @@ <h3 class='fl m0' id='difference'>
 
 
 
+</section>
+
+          
+        
+          
+            <section class='p2 mb2 clearfix bg-white minishadow'>
+
+  
+  <div class='clearfix'>
+    <h3 class='fl m0' id='within'>
+      within
+    </h3>
+    
+  </div>
+  
+
+  <p>Checks if two values are within the given tolerance of each other.</p>
+
+
+  <div class='pre p1 fill-light mt0'>within(a: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>, b: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>, tolerance: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>): <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean">boolean</a></div>
+
+  
+
+  
+  
+  
+  
+  
+
+  
+    <div class='py1 quiet mt1 prose-big'>Parameters</div>
+    <div class='prose'>
+      
+        <div class='space-bottom0'>
+          <div>
+            <span class='code bold'>a</span> <code class='quiet'>(<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>)</code> The first number to check
+
+          </div>
+          
+        </div>
+      
+        <div class='space-bottom0'>
+          <div>
+            <span class='code bold'>b</span> <code class='quiet'>(<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>)</code> The second number to check
+
+          </div>
+          
+        </div>
+      
+        <div class='space-bottom0'>
+          <div>
+            <span class='code bold'>tolerance</span> <code class='quiet'>(<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a>)</code> The tolerance. Anything equal to or less than this is considered within the range.
+
+          </div>
+          
+        </div>
+      
+    </div>
+  
+
+  
+
+  
+    
+      <div class='py1 quiet mt1 prose-big'>Returns</div>
+      <code><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean">boolean</a></code>:
+        True if a is &lt;= tolerance of b.
+
+      
+    
+  
+
+  
+
+  
+
+  
+
+  
+
+  
 </section>
 
 

src/math-toolbox.js

@@ -25,3 +25,4 @@ export { isOdd } from './is-odd'
 export { isEven } from './is-even'
 export { percent } from './percent'
 export { difference } from './difference'
+export { within } from './within'

src/within.js

@@ -0,0 +1,13 @@
+ /**
+ * Checks if two values are within the given tolerance of each other.
+ *
+ * @param {number} a - The first number to check
+ * @param {number} b - The second number to check
+ * @param {number} tolerance - The tolerance. Anything equal to or less than this is considered within the range.
+ * @return {boolean} True if a is <= tolerance of b.
+ */
+function within (a, b, tolerance) {
+  return (Math.abs(a - b) <= tolerance)
+}
+
+export { within }

test/within.test.js

@@ -0,0 +1,7 @@
+import { within } from '../src/math-toolbox'
+
+describe('Checks if two values are within the given tolerance of each other', () => {
+  it('Expect 20.5 and 21 to be within each other with the tolerance 0.5', () => {
+    expect(within(20.5, 21, 0.50)).toBe(true)
+  })
+})