interview-question.js

// You receive the name of a city as a string, and you need to 
// return a string that shows how many times each letter shows 
// up in the string by using an asterisk (*).

// For example:

// "Chicago"  -->  "c:**,h:*,i:*,a:*,g:*,o:*"
// As you can see, the letter c is shown only once, but with 2 
// asterisks.

// The return string should include only the letters (not the 
// dashes, spaces, apostrophes, etc). There should be no spaces 
// in the output, and the different letters are separated by a 
// comma (,) as seen in the example above.

// Note that the return string must list the letters in order 
// of their first appearence in the original string.

// More examples:

// "Bangkok"    -->  "b:*,a:*,n:*,g:*,k:**,o:*"
// "Las Vegas"  -->  "l:*,a:**,s:**,v:*,e:*,g:*"

function getStrings(city){
    return JSON.stringify(city.toLowerCase().replace(/\s/g, '').split('').reduce((pre, cur)=>{
        if(pre.hasOwnProperty(cur)){
            pre[cur] += '*';
        } else if(cur){
            pre[cur] = "*";
        }
        return pre;
    }, {})).replace(/\"/g, "").slice(1,-1);
}

const result = getStrings("Las Vegas");

console.log(result);