code: function constrainPointer (pointer, min, max) {
          return pointer < min ? min : ((pointer > max) ? max : pointer);
      }
docs: Constrains a number within a set of bounds (range of two numbers) or returns the pointer if it is within bounds.
  E.g., If pointer is less than `min` then returns `min`.  If pointer is greater than `max` returns `max`.
  If pointer is within bounds returns `pointer`.
  @function module:sjl.constrainPointer
  @param pointer {Number}
  @param min {Number}
  @param max {Number}
  @returns {Number}