feat(get-query-string-value): add new method

* WIP: Cannot get coverage quite there

* fix(compile): achieved 100% test coverage

Author: dominictwlee

src/get-query-string-value.js

@@ -0,0 +1,28 @@
+export default getQueryStringValue
+
+/**
+ * Original Source: https://stackoverflow.com/questions/901115/
+ *
+ * This method will return the query string value
+ * of the given parameter name
+ *
+ * @param {String} name - The parameter name in query string
+ * @param {String} url - The url with query string
+ * @return {String} - The query string value
+ */
+
+function getQueryStringValue(name, url) {
+
+  name = name.replace(/[\[\]]/g, '\\$&')
+  const regex = new RegExp(`[?&]${name}(=([^&#]*)|&|#|$)`)
+  const results = regex.exec(url)
+  if (!results) {
+    return null
+  }
+
+  if (!results[2]) {
+    return ''
+  }
+
+  return decodeURIComponent(results[2].replace(/\+/g, ' '))
+}

src/index.js

@@ -56,6 +56,7 @@ import isPrime from './is-prime'
 import swapElements from './swapElements'
 import reverse from './reverse'
 import removeAccents from './remove-accents'
+import getQueryStringValue from './get-query-string-value'
 
 export {
   isOdd,
@@ -116,4 +117,5 @@ export {
   swapElements,
   reverse,
   removeAccents,
+  getQueryStringValue,
 }

test/get-query-string-value.test.js

@@ -0,0 +1,32 @@
+import test from 'ava'
+import {getQueryStringValue} from '../src'
+
+const url = 'https://www.google.com/search?foo=bar&bar=&apple'
+
+test('returns query string value of the given parameter', t => {
+  const name = 'foo'
+  const expected = 'bar'
+  const actual = getQueryStringValue(name, url)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if parameter is present with empty value', t => {
+  const name = 'bar'
+  const expected = ''
+  const actual = getQueryStringValue(name, url)
+  t.deepEqual(actual, expected)
+})
+
+test('returns an empty string if parameter is present with no value', t => {
+  const name = 'apple'
+  const expected = ''
+  const actual = getQueryStringValue(name, url)
+  t.deepEqual(actual, expected)
+})
+
+test('returns null if parameter does not exist', t => {
+  const name = 'pizza'
+  const expected = null
+  const actual = getQueryStringValue(name, url)
+  t.deepEqual(actual, expected)
+})