const isUniqueString = str => {
return str.split('').every(el => str.indexOf(el) === str.lastIndexOf(el));
};
const findUniqueString = arr => {
for (let i = 0; i < arr.length; i++) {
if (isUniqueString(arr[i])) {
return arr[i];
};
};
return false;
};
const arr = ['java', 'c++', 'node.js', 'rust', 'c', 'go', 'python'];
console.log(findUniqueString(arr));
/*
run:
node.js
*/