Fibonacci in JavaScript

fibonacci.js

/*function memoization(func){
  let memo = new Map();
  console.log(`counter: ${memo.size}`);

  function memoize(arg){
    console.log(`${arg} is received`);
    let isExist = memo.get(arg);

    if (isExist) {
      return isExist;
    }
    else{
      let v = func(arg);
      memo.set(arg, v);
      return v;
    }
  }

  return memoize;
}*/

function memoization(func){
  let memo = new Map();
  console.log(`counter: ${memo.size}`);

  function memoize(...args){
    console.log(`${args} is received`);
    const key = JSON.stringify(args);

    if (memo.has(key)){
      console.log(`Cache hit: ${key}`);
      return memo.get(key);
    }
    else{
      const v = func.apply(this, args);
      memo.set(key, v);
      return v;
    }
  }

  return memoize;
}

function fibonacci(num){
  switch(num){
    case 0:
    case 1:
      return num;
      break;
    default:
      return fibonacci(num - 1) + fibonacci(num - 2);
  }
}

function memoized_fibonacci(num){
  let memo = new Map();

  function fibonacci_inline(num){
    let isExist = memo.get(num);

    if (isExist === undefined){
      switch(num){
        case 0:
        case 1:
          return num;
        default:
          let v = fibonacci_inline(num - 1) + fibonacci_inline(num - 2);
          memo.set(num, v);
          return v;
      }
    }
    else{
      //console.log(`cache hit!! - ${isExist}`);
      return isExist;
    }
  }

  return fibonacci_inline(num);
}

function tail_rec_fibonacci(num){
  function loop(acc1, acc2, num){
    switch(num){
      case 0:
        return acc1;
      case 1:
        return acc2;
      default:
        return loop(acc2, acc1 + acc2, num - 1);
    }
  }

  return loop(0, 1, num);
}