Once upon a time, on a way through the old wild mountainous west,…
… a man was given directions to go from one point to another. The directions were "NORTH", "SOUTH", "WEST", "EAST". Clearly "NORTH" and "SOUTH" are opposite, "WEST" and "EAST" too.

Going to one direction and coming back the opposite direction right away is a needless effort. Since this is the wild west, with dreadful weather and not much water, it's important to save yourself some energy, otherwise you might die of thirst!

To solve this task, I’m going to use recursion by iterating through the array elements. In each iteration, I’ll check if the current direction is the opposite of the next one. If they are opposites, I’ll remove them from the array and call the function again with the modified data.

function dirReduc(arr){
  let index = 0;
  const oppositeDirMap = {
    WEST: "EAST",
    EAST: "WEST",
    SOUTH: "NORTH",
    NORTH: "SOUTH"
  }
  
  while(index < arr.length) {
    if(arr[index] === oppositeDirMap[arr[index + 1]]){
      arr.splice(index, 2);
      return dirReduc(arr);
    }
    index++;
  }
  return arr;
}

When you watch a senior engineer work with AI tools like Cursor or Copilot, it looks like magic. They can scaffold entire features in minutes, complete with tests and documentation. But watch carefully, and you'll notice something crucial: They're not just accepting what the AI suggests. They're constantly applying years of hard-won engineering wisdom to shape and constrain the AI's output. The AI is accelerating their implementation, but their expertise is what keeps the code maintainable.