Hacker Rank- Day 8th Challenge solved in javascript- Dictionaries and Maps

Here is the problem screen shot

My solution in javascript is

function processData(input) {
let phoneBook = new Map();
let arr = input.split('\n');
let stringValue = '';
for(var i=1; i<arr.length; i++){
let valueSplit = arr[i].split(' ');
if(valueSplit.length>1){
phoneBook.set(valueSplit[0], valueSplit[1])
} else{
if(phoneBook.has(valueSplit[0])){
 stringValue += valueSplit[0]+'='+phoneBook.get(valueSplit[0])+'\n';
} else{
 stringValue += 'Not found'+'\n';
}
}
}
return stringValue;
}

I hope you can find your way with this solution!

Happy Coding!