outline/shared/random.ts

/**
 * Generate a random integer within a given range.
 *
 * @param min - The minimum value of the range.
 * @param max - The maximum value of the range.
 * @returns A random integer within the range.
 */
export const randomInteger = (min: number, max: number) =>
  Math.floor(Math.random() * (max - min + 1) + min);

/**
 * Choose a random element from an array.
 *
 * @param arr - The array to choose from.
 * @returns A random element from the array.
 */
export const randomElement = <T>(arr: T[]): T =>
  arr[randomInteger(0, arr.length - 1)];

type RandomStringOptions = {
  /** The length of the output string. */
  length: number;
  /** The character set to use. */
  charset?: "alphabetic" | "numeric" | "alphanumeric";
  /** The capitalization of the string. */
  capitalization?: "lowercase" | "uppercase" | "mixed";
};

/**
 * Generate a random string of a given length and charset.
 *
 * @param options - The length of the string or an object with options.
 * @returns A random string.
 */
export const randomString = (options: number | RandomStringOptions) => {
  const lowercase = "abcdefghijklmnopqrstuvwxyz";
  const uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  const numeric = "0123456789";

  const length = typeof options === "number" ? options : options.length;
  const charset =
    typeof options === "number"
      ? "alphanumeric"
      : options.charset || "alphanumeric";
  const capitalization =
    typeof options === "number" ? "mixed" : options.capitalization || "mixed";

  const chars =
    charset === "numeric"
      ? numeric
      : charset === "alphabetic"
        ? capitalization === "lowercase"
          ? lowercase
          : capitalization === "uppercase"
            ? uppercase
            : lowercase + uppercase
        : capitalization === "lowercase"
          ? lowercase + numeric
          : capitalization === "uppercase"
            ? uppercase + numeric
            : lowercase + uppercase + numeric;

  const array = new Uint8Array(length);
  // oxlint-disable-next-line no-restricted-globals
  crypto.getRandomValues(array);
  return Array.from(array, (x) => chars[x % chars.length]).join("");
};