Merge pull request #11 from imravichhetri/toUpperCase

toUpperCase implemented

Author: ashokdey

implementations/toUpperCase.js

@@ -0,0 +1,24 @@
+/*
+  The toUpperCase() method returns the value of the string converted to uppercase.
+  This method does not affect the value of the string itself since JavaScript strings are immutable.
+
+
+  MDN Link: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+
+  Characters from A-Z have ASCII code from 65 - 90.
+  And characters from a-z have ASCII code from 97-122.
+  We're checking this condition to implement this function.
+*/
+String.prototype.toUpperCase = function myToUpperCase() {
+  let upperCaseString = '';
+  for (let i = 0; i < this.length; i += 1) {
+    const character = this[i];
+    const charCode = character.charCodeAt();
+    if (charCode >= 97 && charCode <= 122) {
+      upperCaseString += String.fromCharCode(charCode - 32);
+    } else {
+      upperCaseString += character;
+    }
+  }
+  return upperCaseString;
+};