explain this JavaScript code: import Seedrandom from 'seedrandom';
import uniqid from 'uniqid';

const setSeed = (seed: string) => {
	const urlParams = new URLSearchParams(window.location.search);

	urlParams.set('seed', seed);

	const url = `?${urlParams.toString()}`;

	window.history.replaceState(null, 'preference', url);
}

const getInitialSeed = () => {
	const urlParams = new URLSearchParams(window.location.search);

	const seedParam = urlParams.get('seed');

	if (seedParam === null) {
		const seed = uniqid();

		setSeed(seed);

		return seed;
	}

	return seedParam;
}

class Randomizer {

	protected static _seed: string = getInitialSeed();

	protected static _random: CallableFunction;

	public static get random(): any {
		if (!this._random) {
			this.resetRandom();
		}

		return this._random;
	}

	public static get seed(): string {
		return this._seed;
	}

	public static set seed(seed: string) {
		if (seed === this._seed) {
			return;
		}

		if (!seed) {
			seed = uniqid();
		}

		this._seed = seed;

		setSeed(this._seed);
	}

	public static resetRandom(): void {
		this._random = Seedrandom(this.seed);
	}

	public static int(max: number, min: number = 0): number {
		return Math.floor(this.random() * (max - min) + min);
	}

	public static pickOne<T = string>(items: T[]): T {
		const pickedIndex = this.int(items.length);

		return items[pickedIndex];
	}

	public static pickOneWithChance<T = string>(items: Array<[T, number]>): T {
		const fullList = items.reduce<T[]>((acc, [item, count]) => {
			for (let i = 0; i < count; i++) {
				acc.push(item);
			}

			return acc;
		}, []);

		return this.pickOne(fullList);
	}

	public static getChanceStatistics<T = { text: string }>(items: Array<[T, number]>) {
		const fullList = items.reduce<T[]>((acc, [item, count]) => {
			for (let i = 0; i < count; i++) {
				acc.push(item);
			}

			return acc;
		}, []);

		return items.reduce<any>((acc, [item]) => {
			acc[(item as any).text] = fullList.filter(entry => entry === item).length / fullList.length;

			return acc;
		}, {});
	}

}

export default Randomizer;
 Limit your response to 550 words.
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