import type { ArrayVector4D } from "./types.js";
/**
 * Normalizes a 4D vector to unit length.
 * @param {ArrayVector4D} xyzw - Vector as `[x, y, z, w]`
 * @param {number} [m] - Optional current magnitude (default: `magnitude4D(xyzw)`)
 * @returns {ArrayVector4D} The normalized vector
 */
export declare const normalize4D: (xyzw: ArrayVector4D, m?: number) => ArrayVector4D;