Input Direction confusion in snake game javascript

[polaryeti]

Here's the full code:

https://codepen.io/pelko/pen/jOpBmPN

This is the code that I'm interested in:

window.addEventListener("keydown", e => {
  inputDir = { x: 0, y: 1 };
  moveSound.play();
  switch (e.key) {
    case "ArrowUp":
      inputDir.x = 0;
      inputDir.y = -1;
      break;
    case "ArrowDown":
      inputDir.x = 0;
      inputDir.y = 1;
      break;
    case "ArrowLeft":
      inputDir.x = -1;
      inputDir.y = 0;
      break;
    case "ArrowRight":
      inputDir.x = 1;
      inputDir.y = 0;
      break;


  }
})

What is inputDir variable? (I didn't write this code, I'm learning it from a tutorial, you know tutorials don't cover stuffs well).
What I'm not understanding is why are we setting inputDir at 0th row, 1st column? What does that mean? Can you provide some explanations with figures(if possible) about this issue?

 

[polaryeti]

I must tell why my confusion came here:
Earlier in the code, we’ve done this:

//head of snake
let snakeArr = [
  {
    x: 13,
    y: 15
  }
]

Here x,y means the grid row 13, grid column 15. That is why I’m confused. We’re using same variable names in 2 places with different meanings. In this question, we’re using x,y for direction(up,down etc).

How are we able to do this?

 

[Padonak]

Some good reading:

Variable scope
Function scope​

 

[polaryeti]

Some good reading:

Variable scope​

Function scope​

thank you. but it's not related tothis.

 

[polaryeti]

My confusion is cleared.

arrSnake=[{x:0,y:1}]

inputDir={x:0,y:1}

are 2 different object names. It doesn't matter if we use same key name for both of them.