Merge pull request #506 from kriadmin/isUpperCase

[FEATURE] isUpperCase isLowerCase

snippets/isLowerCase.md

@@ -0,0 +1,15 @@
+### isLowerCase
+
+Checks if a string is lower case.
+
+Convert the given string to lower case, using `String.toLowerCase()` and compare it to the original.
+
+``` js
+const isLowerCase = str => str === str.toLowerCase();
+```
+
+```js
+isLowerCase('abc'); // true
+isLowerCase('a3@$'); // true
+isLowerCase('Ab4'); // false
+```

snippets/isUpperCase.md

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+### isUpperCase
+
+Checks if a string is upper case.
+
+Convert the given string to upper case, using `String.toUpperCase()` and compare it to the original.
+
+
+``` js
+const isUpperCase = str => str === str.toUpperCase();
+```
+
+``` js
+isUpperCase('ABC'); // true
+isLowerCase('A3@$'); // true
+isLowerCase('aB4'); // false
+```