Vector.js

function Vector(x,y) {
  this.x = x
  this.y = y
}
Vector.prototype.plus = function(other) {
  return new Vector(this.x + other.x, this.y + other.y)
};
Vector.prototype.minus = function(other) {
  return new Vector(this.x - other.x, this.y - other.y)
};
Object.defineProperty(Vector.prototype, "length", {
  get: function() { return Math.sqrt((this.x * this.x) + (this.y * this.y)) }
});
console.log(new Vector(1, 2).plus(new Vector(2, 3)));
// → Vector{x: 3, y: 5}
console.log(new Vector(1, 2).minus(new Vector(2, 3)));
// → Vector{x: -1, y: -1}
console.log(new Vector(3, 4).length);
// → 5


// Your code here.
function ISeq() {}
ISeq.prototype.next = function () {
  console.log("Returns next value");
};
ISeq.prototype.hasNext = function() {
  console.log("true if there is more elements left in the sequence");
}

function ArraySeq(arr) {
  this.arr = arr;
  this.curr = 0;
};
ArraySeq.prototype = Object.create(ISeq.prototype);
ArraySeq.prototype.next = function() {
  var res = this.arr[this.curr];
  this.curr += 1;
  return res;
};
ArraySeq.prototype.hasNext = function() {
  if (this.curr < this.arr.length) {    
    return true;
  } else {
    return false;
  }
};

function logFive(seq) {
  var count = 0;
  while(seq.hasNext() && count < 5) {
    console.log(seq.next());
    count += 1;
  }
}

logFive(new ArraySeq([1, 2, 3, 4, 5, 6]));