Uncaught TypeError: Cannot read property 'x' of undefined

[autergame]

i am new in this forum

var boundariesg = [];
boundariesg.push(new Boundary(mouseX, mouseY, 200, 20, anglee / PI));
Body.setPosition(boundariesg[1], { x: mouseX, y: mouseY });

---boundarie code---

function Boundary(x, y, w, h, a) {
  var options = {
    friction: 0,
    restitution: 0.90,
    angle: a,
    isStatic: true
  }
  this.body = Bodies.rectangle(x, y, w, h, options);
  this.w = w;
  this.h = h;
  World.add(world, this.body);

  this.removeFromWorld = function() {
    World.remove(world, this.body);
  }

  this.show = function() {
    var pos = this.body.position;
    var angle = this.body.angle;
    push();
    translate(pos.x, pos.y);
    rotate(angle);
    rectMode(CENTER);
    strokeWeight(1);
    noStroke();
    fill(0);
    rect(0, 0, this.w, this.h);
    pop();
  }

}

[liabru]

Looks like it should be Body.setPosition(boundariesg[1].body, { x: mouseX, y: mouseY });?