lengthSq() {

		return this._x * this._x + this._y * this._y + this._z * this._z + this._w * this._w;

	}
Computes the squared Euclidean length (straight-line length) of this quaternion,
considered as a 4 dimensional vector. This can be useful if you are comparing the
lengths of two quaternions, as this is a slightly more efficient calculation than
{@link Quaternion#length}.

@return {number} The squared Euclidean length.