📅 TIL #4

let output = flattenArr([[1], 2, [3, 4], 5]);
console.log(output); // --> [1, 2, 3, 4, 5]

output = flattenArr([[2, [[3]]], 4, [[[5]]]);
console.log(output); // --> [2, 3, 4, 5]

let resultArr = [];

if (arr.length === 0) {
  return [];
}

for (let i = 0; i < arr.length; i++) {
  if (Array.isArray(arr[i])) {
    const result = flattenArr(arr[i]);
    resultArr.push(...result);
  } else {
    resultArr.push(arr[i]);
  }
}

return resultArr;

return arr.reduce(function(acc, cur) {
  return acc.concat(Array.isArray(cur) ? flattenArr(cur) : cur);
},[]);
}

let output = isIsogram("aba");
console.log(output); // false

output = isIsogram("Dermatoglyphics");
console.log(output); // true

if (str === "") {
  return true;
}

let upper = str.toUpperCase();

for (let i = 0; i < upper.length; i++) {
  for (let j = i + 1; j < upper.length; j++) {
    if (upper[i] === upper[j]) {
      return false;
    }
  }
}
return true;

if (str.length === 0) {
  return true;
}

let cache = {};
let strLowered = str.toLowerCase();

for (let i = 0; i < strLowered.length; i++) {
  if (cache[strLowered[i]]) {
    return false;
  }
  cache[strLowered[i]] = true;
}

return true;