feat: randomSign()

Author: terkelg

README.md

@@ -76,6 +76,7 @@ https://unpkg.com/math-toolbox/dist/math-toolbox.umd.min.js
 | 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 |
+| randomSign | Returns either 1 or -1 |
 
 ## Plans
 See GitHub Wiki:

docs/index.html

@@ -303,6 +303,16 @@ <h3 class='mb0 no-anchor'></h3>
 
                 </li>
 
+                
+                <li><a
+                  href='#randomsign'
+                  class="">
+                  randomSign
+                  
+                </a>
+                
+                </li>
+              
             </ul>
           </div>
           <div class='mt1 h6 quiet'>
@@ -2462,6 +2472,58 @@ <h3 class='fl m0' id='within'>
 
 
 
+</section>
+
+          
+        
+          
+            <section class='p2 mb2 clearfix bg-white minishadow'>
+
+  
+  <div class='clearfix'>
+    <h3 class='fl m0' id='randomsign'>
+      randomSign
+    </h3>
+    
+  </div>
+  
+
+  <p>Generate random sign (1 or -1)</p>
+
+
+  <div class='pre p1 fill-light mt0'>randomSign(): <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number">number</a></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/Number">number</a></code>:
+        Either 1 or -1
+
+      
+    
+  
+
+  
+
+  
+
+  
+
+  
+
+  
 </section>
 
 

src/math-toolbox.js

@@ -26,3 +26,4 @@ export { isEven } from './is-even'
 export { percent } from './percent'
 export { difference } from './difference'
 export { within } from './within'
+export { randomSign } from './random-sign'

src/random-sign.js

@@ -0,0 +1,10 @@
+/**
+ * Generate random sign (1 or -1)
+ *
+ * @return {number} Either 1 or -1
+ */
+function randomSign () {
+  return (Math.random() > 0.5) ? 1 : -1
+}
+
+export { randomSign }

test/random-sign.test.js

@@ -0,0 +1,13 @@
+import { randomSign } from '../src/math-toolbox'
+
+describe('Return random sign 1 or -1', () => {
+  let sign = randomSign()
+
+  it('Should be greater than or equal to -1', () => {
+    expect(sign).toBeGreaterThanOrEqual(-1)
+  })
+
+  it('Should be less than or equal to 1', () => {
+    expect(sign).toBeLessThanOrEqual(1)
+  })
+})