construct Object From String

constructObjectFromString.md

Given a string, return an Object whose keys are the characters and the values are the frequency of each the character present in the string. For eg.

let str = "vivek";
function buildObjectFromString(str){
// write your code here
}
buildObjectFromString(str);

// should return 
{
 "v" :2,
 "i" :1,
 "e" :1,
 "k" :1
}