converting string to camel case

main.js

// util function to convert the input to string type
function convertToString(input) {
  
      if(input) { 
        
           if(typeof input === "string") {
 
                return input;
            }
          
           return String(input);
      }
      return '';
}


// convert string to words
function toWords(input) {							
  
   input = convertToString(input);
   
   var regex = /[A-Z\xC0-\xD6\xD8-\xDE]?[a-z\xDF-\xF6\xF8-\xFF]+|[A-Z\xC0-\xD6\xD8-\xDE]+(?![a-z\xDF-\xF6\xF8-\xFF])|\d+/g;
   
   return input.match(regex);
  
}


// convert the input array to camel case
function toCamelCase(inputArray) {

    let result = "";

    for(let i = 0 , len = inputArray.length; i < len; i++) {

      let currentStr = inputArray[i];
	
      let tempStr = currentStr.toLowerCase();

      if(i != 0) {
	
        // convert first letter to upper case (the word is in lowercase) 
          tempStr = tempStr.substr(0, 1).toUpperCase() + tempStr.substr(1);

       }
      
       result +=tempStr;
      
    }
  
    return result;
}
  

// this function call all other functions

function toCamelCaseString(input) {						
  
  let words = toWords(input);
  
  return toCamelCase(words);
  
}

nonASCII regex

/(?:[\x41-\x5a\xc0-\xd6\xd8-\xde\u0100\u0102\u0104\u0106\u0108\u010a\u010c\u010e\u0110\u0112\u0114\u0116\u0118\u011a\u011c\u011e\u0120\u0122\u0124\u0126\u0128\u012a\u012c\u012e\u0130\u0132\u0134\u0136\u0139\u013b\u013d\u013f\u0141\u0143\u0145\u0147\u014a\u014c\u014e\u0150\u0152\u0154\u0156\u0158\u015a\u015c\u015e\u0160\u0162\u0164\u0166\u0168\u016a\u016c\u016e\u0170\u0172\u0174\u0176\u0178\u0179\u017b\u017d\u0181\u0182\u0184\u0186\u0187\u0189-\u018b\u018e-\u0191\u0193\u0194\u0196-\u0198\u019c\u019d\u019f\u01a0\u01a2\u01a4\u01a6\u01a7\u01a9\u01ac\u01ae\u01af\u01b1-\u01b3\u01b5\u01b7\u01b8\u01bc\u01c4\u01c5\u01c7\u01c8\u01ca\u01cb\u01cd\u01cf\u01d1\u01d3\u01d5\u01d7\u01d9\u01db\u01de\u01e0\u01e2\u01e4\u01e6\u01e8\u01ea\u01ec\u01ee\u01f1\u01f2\u01f4\u01f6-\u01f8\u01fa\u01fc\u01fe\u0200\u0202\u0204\u0206\u0208\u020a\u020c\u020e\u0210\u0212\u0214\u0216\u0218\u021a\u021c\u021e\u0220\u0222\u0224\u0226\u0228\u022a\u022c\u022e\u0230\u0232\u023a\u023b\u023d\u023e\u0241\u0243-\u0246\u0248\u024a\u024c\u024e][\u0300-\u036F\u1AB0-\u1AFF\u1DC0-\u1DFF\u20D0-\u20FF\uFE20-\uFE2F]*)?(?:[a-z\xB5\xDF-\xF6\xF8-\xFF\u0101\u0103\u0105\u0107\u0109\u010B\u010D\u010F\u0111\u0113\u0115\u0117\u0119\u011B\u011D\u011F\u0121\u0123\u0125\u0127\u0129\u012B\u012D\u012F\u0131\u0133\u0135\u0137\u0138\u013A\u013C\u013E\u0140\u0142\u0144\u0146\u0148\u0149\u014B\u014D\u014F\u0151\u0153\u0155\u0157\u0159\u015B\u015D\u015F\u0161\u0163\u0165\u0167\u0169\u016B\u016D\u016F\u0171\u0173\u0175\u0177\u017A\u017C\u017E-\u0180\u0183\u0185\u0188\u018C\u018D\u0192\u0195\u0199-\u019B\u019E\u01A1\u01A3\u01A5\u01A8\u01AA\u01AB\u01AD\u01B0\u01B4\u01B6\u01B9\u01BA\u01BD-\u01BF\u01C6\u01C9\u01CC\u01CE\u01D0\u01D2\u01D4\u01D6\u01D8\u01DA\u01DC\u01DD\u01DF\u01E1\u01E3\u01E5\u01E7\u01E9\u01EB\u01ED\u01EF\u01F0\u01F3\u01F5\u01F9\u01FB\u01FD\u01FF\u0201\u0203\u0205\u0207\u0209\u020B\u020D\u020F\u0211\u0213\u0215\u0217\u0219\u021B\u021D\u021F\u0221\u0223\u0225\u0227\u0229\u022B\u022D\u022F\u0231\u0233-\u0239\u023C\u023F\u0240\u0242\u0247\u0249\u024B\u024D\u024F][\u0300-\u036F\u1AB0-\u1AFF\u1DC0-\u1DFF\u20D0-\u20FF\uFE20-\uFE2F]*)+|(?:[\x41-\x5a\xc0-\xd6\xd8-\xde\u0100\u0102\u0104\u0106\u0108\u010a\u010c\u010e\u0110\u0112\u0114\u0116\u0118\u011a\u011c\u011e\u0120\u0122\u0124\u0126\u0128\u012a\u012c\u012e\u0130\u0132\u0134\u0136\u0139\u013b\u013d\u013f\u0141\u0143\u0145\u0147\u014a\u014c\u014e\u0150\u0152\u0154\u0156\u0158\u015a\u015c\u015e\u0160\u0162\u0164\u0166\u0168\u016a\u016c\u016e\u0170\u0172\u0174\u0176\u0178\u0179\u017b\u017d\u0181\u0182\u0184\u0186\u0187\u0189-\u018b\u018e-\u0191\u0193\u0194\u0196-\u0198\u019c\u019d\u019f\u01a0\u01a2\u01a4\u01a6\u01a7\u01a9\u01ac\u01ae\u01af\u01b1-\u01b3\u01b5\u01b7\u01b8\u01bc\u01c4\u01c5\u01c7\u01c8\u01ca\u01cb\u01cd\u01cf\u01d1\u01d3\u01d5\u01d7\u01d9\u01db\u01de\u01e0\u01e2\u01e4\u01e6\u01e8\u01ea\u01ec\u01ee\u01f1\u01f2\u01f4\u01f6-\u01f8\u01fa\u01fc\u01fe\u0200\u0202\u0204\u0206\u0208\u020a\u020c\u020e\u0210\u0212\u0214\u0216\u0218\u021a\u021c\u021e\u0220\u0222\u0224\u0226\u0228\u022a\u022c\u022e\u0230\u0232\u023a\u023b\u023d\u023e\u0241\u0243-\u0246\u0248\u024a\u024c\u024e][\u0300-\u036F\u1AB0-\u1AFF\u1DC0-\u1DFF\u20D0-\u20FF\uFE20-\uFE2F]*)+(?![a-z\xB5\xDF-\xF6\xF8-\xFF\u0101\u0103\u0105\u0107\u0109\u010B\u010D\u010F\u0111\u0113\u0115\u0117\u0119\u011B\u011D\u011F\u0121\u0123\u0125\u0127\u0129\u012B\u012D\u012F\u0131\u0133\u0135\u0137\u0138\u013A\u013C\u013E\u0140\u0142\u0144\u0146\u0148\u0149\u014B\u014D\u014F\u0151\u0153\u0155\u0157\u0159\u015B\u015D\u015F\u0161\u0163\u0165\u0167\u0169\u016B\u016D\u016F\u0171\u0173\u0175\u0177\u017A\u017C\u017E-\u0180\u0183\u0185\u0188\u018C\u018D\u0192\u0195\u0199-\u019B\u019E\u01A1\u01A3\u01A5\u01A8\u01AA\u01AB\u01AD\u01B0\u01B4\u01B6\u01B9\u01BA\u01BD-\u01BF\u01C6\u01C9\u01CC\u01CE\u01D0\u01D2\u01D4\u01D6\u01D8\u01DA\u01DC\u01DD\u01DF\u01E1\u01E3\u01E5\u01E7\u01E9\u01EB\u01ED\u01EF\u01F0\u01F3\u01F5\u01F9\u01FB\u01FD\u01FF\u0201\u0203\u0205\u0207\u0209\u020B\u020D\u020F\u0211\u0213\u0215\u0217\u0219\u021B\u021D\u021F\u0221\u0223\u0225\u0227\u0229\u022B\u022D\u022F\u0231\u0233-\u0239\u023C\u023F\u0240\u0242\u0247\u0249\u024B\u024D\u024F])|[\d]+|[\u2700-\u27BF]|[^\x00-\x2F\x3A-\x40\x5B-\x60\x7b-\xBF\xD7\xF7\u2000-\u206F\s\uFEFF\xA0]+/g

function convertToString(input){
if (input){
if (typeof input === "string"){
return input;
}
return String (input);
}
return '';
}

function toWords(input){
input = convertToString(input);
var regex = /[A-Z\xC0-\xD6\xD8-\xDE]?[a-z\xDF-\xF6\xF8-\xFF]+[A-Z\xC0-\xD6\xD8-\xDE]+(?![a-z\xDF-\xF8-\xFF])\d+/g;

return input.match(regex);

}

function toCamelCase(inputArray){
let result = "";
for (let i = 0, len = inputArray.length; i<len; i++){
let currenStr = inputArray[i];
let tempStr = currenStr.toLowerCase();
if (i!=0){
tempStr = tempStr.substr(0,1).toUpperCase()+tempStr.substr(1);
}
result += tempStr;
}
return result;

}

function toCamelCaseString(input){
let words = toWords(input);
return toCamelCase(words);
}