Additional snippets

README.md

@@ -6,6 +6,44 @@
 - Use <kbd>Ctrl</kbd> + <kbd>F</kbd> or <kbd>command</kbd> + <kbd>F</kbd> to search for a snippet.
 - Contributions welcome, please read [contribution guide](contributing.md).
 
+## Contents
+
+* [Even or odd number](even-or-odd-number.md)
+* [Greatest common divisor gcd](greatest-common-divisor-gcd.md)
+* [RGB to hexadecimal](RGB-to-hexadecimal.md)
+* [Sort characters in string alphabetical](sort-characters-in-string-alphabetical.md)
+* [Sum of array of numbers](sum-of-array-of-numbers.md)
+* [Unique values of array](unique-values-of-array.md)
+
+### Even or odd number
+
+Use `Math.abs()` to extend logic to negative numbers, check using the modulo (`%`) operator.
+Return `true` if the number is even, `false` if the number is odd.
+
+```js
+var isEven = num => Math.abs(num) % 2 === 0;
+```
+
+## Greatest common divisor (GCD)
+
+Use recursion.
+Base case is when `y` equals `0`. In this case, return `x`.
+Otherwise, return the GCD of `y` and the remainder of the division `x/y`.
+
+```js
+var gcd = (x , y) => !y ? x : gcd(y, x % y);
+```
+
+## RGB to hexadecimal
+
+Convert each value to a hexadecimal string, using `toString(16)`, then `padStart(2,'0')` to get a 2-digit hexadecimal value.
+Combine values using `join('')`.
+
+```js
+var rgbToHex = (r, g, b) =>
+  [r.toString(16).padStart(2,'0') , g.toString(16).padStart(2,'0') , b.toString(16).padStart(2,'0')].join('');
+```
+
 ### Sort characters in string (alphabetical)
 
 Split the string using `split('')`, `sort()` utilizing `localeCompare()`, recombine using `join('')`.
@@ -15,6 +53,29 @@ var sortCharactersInString = str =>
   str.split('').sort( (a,b) => a.localeCompare(b) ).join('');
 ```
 
+### Sum of array of numbers
+
+Use `reduce()` to add each value to an accumulator, initialized with a value of `0`.
+
+```js
+var sum = arr =>
+  arr.reduce( (acc , val) => acc + val, 0);
+```
+
+### Unique values of array
+
+Use `reduce()` to accumulate all unique values in an array.
+Check if each value has already been added, using `indexOf()` on the accumulator array.
+
+```js
+var uniqueValues = arr =>
+  arr.reduce( (acc, val) => {
+    if(acc.indexOf(val) === -1)
+      acc.push(val);
+      return acc;
+  }, []);
+```
+
 ## Credits
 
 *Icons made by [Smashicons](https://www.flaticon.com/authors/smashicons) from [www.flaticon.com](https://www.flaticon.com/) is licensed by [CC 3.0 BY](http://creativecommons.org/licenses/by/3.0/).*

scripts/builder.js

@@ -27,6 +27,9 @@ catch (err){
 
 try {
   output += `${startPart+'\n'}`;
+  for(var snippet of Object.entries(snippets))
+    output += `* [${snippet[0][0].toUpperCase() + snippet[0].replace(/-/g,' ').slice(1,snippet[0].length-3)}](${snippet[0]})\n`
+  output += '\n';
   for(var snippet of Object.entries(snippets))
     output += `${snippet[1]+'\n'}`;
   output += `${endPart+'\n'}`;

snippets/RGB-to-hexadecimal.md

@@ -0,0 +1,9 @@
+## RGB to hexadecimal
+
+Convert each value to a hexadecimal string, using `toString(16)`, then `padStart(2,'0')` to get a 2-digit hexadecimal value.
+Combine values using `join('')`.
+
+```js
+var rgbToHex = (r, g, b) =>
+  [r.toString(16).padStart(2,'0') , g.toString(16).padStart(2,'0') , b.toString(16).padStart(2,'0')].join('');
+```

snippets/even-or-odd-number.md

@@ -0,0 +1,8 @@
+### Even or odd number
+
+Use `Math.abs()` to extend logic to negative numbers, check using the modulo (`%`) operator.
+Return `true` if the number is even, `false` if the number is odd.
+
+```js
+var isEven = num => Math.abs(num) % 2 === 0;
+```

snippets/greatest-common-divisor-gcd.md

@@ -0,0 +1,9 @@
+## Greatest common divisor (GCD)
+
+Use recursion.
+Base case is when `y` equals `0`. In this case, return `x`.
+Otherwise, return the GCD of `y` and the remainder of the division `x/y`.
+
+```js
+var gcd = (x , y) => !y ? x : gcd(y, x % y);
+```

snippets/sum-of-array-of-numbers.md

@@ -0,0 +1,8 @@
+### Sum of array of numbers
+
+Use `reduce()` to add each value to an accumulator, initialized with a value of `0`.
+
+```js
+var sum = arr =>
+  arr.reduce( (acc , val) => acc + val, 0);
+```

snippets/unique-values-of-array.md

@@ -0,0 +1,13 @@
+### Unique values of array
+
+Use `reduce()` to accumulate all unique values in an array.
+Check if each value has already been added, using `indexOf()` on the accumulator array.
+
+```js
+var uniqueValues = arr =>
+  arr.reduce( (acc, val) => {
+    if(acc.indexOf(val) === -1)
+      acc.push(val);
+      return acc;
+  }, []);
+```

static-parts/README-start.md

@@ -5,3 +5,5 @@
 
 - Use <kbd>Ctrl</kbd> + <kbd>F</kbd> or <kbd>command</kbd> + <kbd>F</kbd> to search for a snippet.
 - Contributions welcome, please read [contribution guide](contributing.md).
+
+## Contents