add new

Author: abranhe

docs/complementary-dna.md

@@ -0,0 +1,40 @@
+# complementary-dna
+
+Deoxyribonucleic acid (DNA) is a chemical found in the nucleus of cells and carries the "instructions" for the development and functioning of living organisms.
+
+If you want to know more http://en.wikipedia.org/wiki/DNA
+
+In DNA strings, symbols "A" and "T" are complements of each other, as "C" and "G". You have function with one side of the DNA (string, except for Haskell); you need to get the other complementary side. DNA strand is never empty or there is no DNA at all (again, except for Haskell).
+
+More similar exercise are found here http://rosalind.info/problems/list-view/
+
+```js
+complementaryDNA("ATTGC") 
+// return "TAACG"
+
+complementaryDNA("GTAT") 
+// return "CATA" 
+```
+
+## Install
+
+```
+$ npm install @abranhe/codewars
+```
+
+## Usage
+
+```js
+const codewars = require('@abranhe/codewars');
+
+codewars.complementaryDNA('ATTGC');
+//=> 'TAACG'
+```
+
+## API
+
+### codewars.complementaryDNA(input)
+
+#### input
+
+Type: `string`

readme.md

@@ -28,6 +28,7 @@ codewars.maskify('454233223424324');
 - [codewars.maskify()](docs/credit-card-mask.md)
 - [codewars.spinWords()](docs/spin-words.md)
 - [codewars.squareDigit()](docs/square-every-digit.md)
+- [codewars.complementaryDNA()](docs/complementary-dna.md)
 
 ## License
 

src/complementary-dna.js

@@ -0,0 +1,8 @@
+module.exports = dna => {
+	return dna
+		.split('')
+		.map(c => {
+			return c === 'A' ? 'T' : c === 'T' ? 'A' : c === 'G' ? 'C' : 'G';
+		})
+		.join('');
+};

src/index.js

@@ -3,9 +3,11 @@
 const maskify = require('./credit-card-mask');
 const spinWords = require('./spin-words');
 const squareDigits = require('./square-every-digit');
+const complementaryDNA = require('./complementary-dna');
 
 module.exports = {
 	maskify,
 	spinWords,
 	squareDigits,
+	complementaryDNA
 };

src/square-every-digit.js

@@ -1,3 +1,3 @@
-module.exports = (input) => {
-	return Number(`${input}`.split('').map((c) => (c **= 2)).join(''));
+module.exports = input => {
+	return Number(`${input}`.split('').map(c => (c * c)).join(''));
 };

tests/complementary-dna.test.js

@@ -0,0 +1,8 @@
+import test from 'ava';
+import {complementaryDNA} from '../src';
+
+test('Check complementary-dna.js', t => {
+	t.is(complementaryDNA('AAAA'), 'TTTT', 'String AAAA is');
+	t.is(complementaryDNA('ATTGC'), 'TAACG', 'String ATTGC is');
+	t.is(complementaryDNA('GTAT'), 'CATA', 'String GTAT is');
+});

tests/square-every-digit.test.js

@@ -1,6 +1,6 @@
 import test from 'ava';
-import { squareDigits } from '../src';
+import {squareDigits} from '../src';
 
 test('Check square-every-digit.js', t => {
-    t.is(squareDigits(9119), 811181);
+	t.is(squareDigits(9119), 811181);
 });