nhb-toolbox/dist/esm/utils/Paginator.js

A versatile collection of smart, efficient, and reusable utility functions, classes and types for everyday development needs.

export class Paginator {
    #totalItems;
    #perPage;
    #currentPage;
    constructor(options) {
        const { totalItems, itemsPerPage = 10, currentPage = 1 } = options ?? {};
        this.#totalItems = Math.max(0, Number(totalItems));
        this.#perPage = Math.max(1, Number(itemsPerPage));
        this.#currentPage = Math.max(1, Number(currentPage));
    }
    withPage(page) {
        const safePage = Math.min(Math.max(1, page), this.totalPages());
        return new Paginator({
            totalItems: this.#totalItems,
            itemsPerPage: this.#perPage,
            currentPage: safePage,
        });
    }
    withPerPage(perPage) {
        const safePerPage = Math.max(1, perPage);
        return new Paginator({
            totalItems: this.#totalItems,
            itemsPerPage: safePerPage,
            currentPage: this.#currentPage,
        });
    }
    withTotalItems(totalItems) {
        const safeTotalItems = Math.max(0, totalItems);
        return new Paginator({
            totalItems: safeTotalItems,
            itemsPerPage: this.#perPage,
            currentPage: this.#currentPage,
        });
    }
    withOptions(options) {
        const newTotalItems = Math.max(0, options.totalItems ? Number(options.totalItems) : this.#totalItems);
        const newItemsPerPage = Math.max(1, options.itemsPerPage ? Number(options.itemsPerPage) : this.#perPage);
        const totalPages = Math.ceil(newTotalItems / newItemsPerPage);
        const newCurrentPage = Math.min(Math.max(1, options.currentPage ? Number(options.currentPage) : this.#currentPage), totalPages);
        return new Paginator({
            totalItems: newTotalItems,
            itemsPerPage: newItemsPerPage,
            currentPage: newCurrentPage,
        });
    }
    offset() {
        return (this.#currentPage - 1) * this.#perPage;
    }
    getOffset() {
        return this.offset();
    }
    skipCount() {
        return this.offset();
    }
    totalPages() {
        return Math.ceil(this.#totalItems / this.#perPage);
    }
    getMeta() {
        const totalPages = this.totalPages();
        return {
            totalItems: this.#totalItems,
            currentPage: this.#currentPage,
            itemsPerPage: this.#perPage,
            totalPages,
            hasPrev: this.hasPrevPage(),
            hasNext: this.hasNextPage(),
            isFirst: this.isFirstPage(),
            isLast: this.isLastPage(),
            offset: this.offset(),
        };
    }
    nextPage() {
        return this.#currentPage < this.totalPages() ? this.#currentPage + 1 : null;
    }
    prevPage() {
        return this.#currentPage > 1 ? this.#currentPage - 1 : null;
    }
    isFirstPage() {
        return this.#currentPage === 1;
    }
    isLastPage() {
        return this.#currentPage === this.totalPages();
    }
    hasPrevPage() {
        return this.#currentPage > 1;
    }
    hasNextPage() {
        return this.#currentPage < this.totalPages();
    }
    pageList(options = {}) {
        const total = this.totalPages();
        const edgeCount = Math.max(0, options.edgeCount ?? 1);
        const siblingCount = Math.max(0, options.siblingCount ?? 1);
        const start = Math.max(this.#currentPage - siblingCount, edgeCount + 1);
        const end = Math.min(this.#currentPage + siblingCount, total - edgeCount);
        const _getRange = (from, to) => {
            return from > to ? [] : Array.from({ length: to - from + 1 }, (_, i) => from + i);
        };
        const startPages = _getRange(1, edgeCount);
        const middlePages = _getRange(start, end);
        const endPages = _getRange(total - edgeCount + 1, total);
        const pages = new Set([...startPages, ...middlePages, ...endPages]);
        return Array.from(pages).sort((a, b) => a - b);
    }
    firstPage() {
        return 1;
    }
    lastPage() {
        return this.totalPages();
    }
    isPageValid(page) {
        const p = Math.floor(page);
        return p >= 1 && p <= this.totalPages();
    }
    static fromMeta(meta) {
        return new Paginator({
            totalItems: meta.totalItems,
            itemsPerPage: meta.itemsPerPage,
            currentPage: meta.currentPage,
        });
    }
}