The main idea is to count all the occurring characters in a string. If you have a string like aba, then the result should be {'a': 2, 'b': 1}.
What if the string is empty? Then the result should be empty object literal, {}.
function count (string) {
// The function code should be here
let obj = {}
for (let i = 0; i < string.length; i++) {
if (!(string[i] in obj)) {
obj[string[i]] = 1
}
else {
obj[string[i]]++
}
}
return obj
}