text: const mystery = (a, b) => {
      let result = '';
      if (typeof a === 'number') {
          if (typeof b === 'number') {
              result = 'path 1';
          } else {
              result = 'path 2';
          }
      } else {
          if (typeof a === typeof b) {
              result = 'path 3';
          } else {
              result = 'path 4';
          }
      }
      return result;
  };
  
  // path 1
  const _1_expect = 'path 1';
  const _1_actual = mystery(0, 1);
  console.assert(_1_actual === _1_expect, 'Test 1');
  
  const _2_expect = 'path 1';
  const _2_actual = mystery(3, 4);
  console.assert(_2_actual === _2_expect, 'Test 2');
  
  // path 2
  const _3_expect = 'path 2';
  const _3_actual = mystery(1, undefined);
  console.assert(_3_actual === _3_expect, 'Test 3');
  
  const _4_expect = 'path 2';
  const _4_actual = mystery(1, true);
  console.assert(_4_actual === _4_expect, 'Test 4');
  
  // path 3
  const _5_expect = 'path 3';
  const _5_actual = mystery('', '');
  console.assert(_5_actual === _5_expect, 'Test 5');
  
  const _6_expect = 'path 3';
  const _6_actual = mystery('_6_expect', '_6_actual');
  console.assert(_6_actual === _6_expect, 'Test 6');
  
  // path 4
  const _7_expect = 'path 4';
  const _7_actual = mystery(true, '');
  console.assert(_7_actual === _7_expect, 'Test 7');
  
  const _8_expect = 'path 4';
  const _8_actual = mystery(null, undefined);
  console.assert(_8_actual === _8_expect, 'Test 8');