React Redux keeps returning multiple reducer objects

I'm trying to render just one object property but it ends up renderings all other objects undefined aside from the targeted property. I'm fairly new to Redux, reducers, etc so any help would be great!

// Letters reducer 
export default function() {
return [
    {
      x: {
        start: 10,
        finish: 100
      }
    },
    {
      y: {
        start: 20,
        finish: 100
      }
    },
    {
      z: {
        start: 30,
        finish: 100
      }
    }
  ];
}

The component

renderList() {
  this.props.letters.map(i => {
    console.log(i.x.start);
  });
}

the console out is

{current: 10, goal: 100}
2 undefined  < -- my Y and Z, which idk why it's getting called.

but if I try calling it like this it works

console.log(this.props.letters[0].x.start)
// 10