code: function(returnNew) {
        var length = this.length();
  
        // Collect a ratio to shrink the x and y coords
        var invertedLength = (length < Number.MIN_VALUE) ? 0 : 1/length;
  
        if (!returnNew) {
          // Convert the coords to be greater than zero
          // but smaller than or equal to 1.0
          return this.set(this.x * invertedLength, this.y * invertedLength);
        } else {
          return new Vec2(this.x * invertedLength, this.y * invertedLength);
        }
      }
docs: Convert this vector into a unit vector. Returns the length.