@mhellams/mth-pagination

v1.0.0

Published

a year ago

### Overview mth-pagination is a class written in TypeScript that provides functionality for managing pagination in your applications. The mth-pagination class generates a range of page numbers and provides methods to navigate between pages.

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mhellams

MTH Pagination

Overview

mth-pagination is a class written in TypeScript that provides functionality for managing pagination in your applications. The mth-pagination class generates a range of page numbers and provides methods to navigate between pages.

Features

Provides a range of page numbers for pagination
Allows customizing the number of page boundaries and sibling pages
Handles page changes, with a callback function to manage what happens on each page change
Includes methods for setting the current page and navigating to the next, previous, first, and last page

Install

Using npm, yarn, or pnpm

npm install @mhellams/mth-pagination
yarn add @mhellams/mth-pagination
pnpm add @mhellams/mth-pagination

Using CDN

<html>
	<head>
		<script src="https://unpkg.com/@mhellams/mth-pagination"></script>
		<script>
		  const pagination = new mthPagination({
			total: 1000,
			page: 1,
			siblings: 2,
			boundaries: 2,
			onChange(page) {
			  console.log(page);
			},
		  });
    </script>
	</head>
</html>

Importing

esm

	import (MthPagination} from '@mhellams/mth-pagination';

cjs

const {MthPagination} = require('@mhellams/mth-pagination')

Usage

import { MthPagination, type PaginationParams } from 'mth-pagination';

const params: PaginationParams = {
  page: 1,
  total: 10,
  siblings: 1,
  boundaries: 1,
  onChange: (page: number) => console.log(`Current page is ${page}`),
};

const pagination = new MthPagination(params);

pagination.range; // -> [1, 2, 3, 4, 5, 'dots', 10];

pagination.setPage(5);
pagination.range; // -> [1, 'dots', 4, 5, 6, 'dots', 10];

pagination.next();
pagination.range; // -> [1, 'dots', 5, 6, 7, 'dots', 10];

pagination.previous();
pagination.range; // -> [1, 'dots', 4, 5, 6, 'dots', 10];

pagination.last();
pagination.range; // -> [1, 'dots', 6, 7, 8, 9, 10];

pagination.first();
pagination.range; // -> [1, 2, 3, 4, 5, 'dots', 10];

Siblings

	const pagination = new MthPagination({ total: 20, siblings: 3 });

Boundaries

	const pagination = new MthPagination({ total: 20, boundaries: 3 });

Definition

export const DOTS = 'dots';

function range(start: number, end: number) {
  const length = end - start + 1;
  return Array.from({ length }, (_, index) => index + start);
}

export interface PaginationParams {
  /** Controlled active page number */
  page?: number;

  /** Total amount of pages */
  total: number;

  /** Siblings amount on left/right side of selected page, defaults to 1 */
  siblings?: number;

  /** Amount of elements visible on left/right edges, defaults to 1  */
  boundaries?: number;

  /** Callback fired after change of each page */
  onChange?: (page: number) => void;
}

export class MthPagination {
  total: number;
  page: number;
  siblings: number;
  boundaries: number;
  private _total: number;
  activePage: number;
  onChange: ((page: number) => void) | undefined;

  constructor({
    boundaries = 1,
    onChange,
    page = 1,
    siblings = 1,
    total,
  }: PaginationParams) {
    this.boundaries = boundaries;
    this.page = page;
    this.siblings = siblings;
    this.total = total;
    this.onChange = onChange;
    this._total = Math.max(Math.trunc(total), 0);
    this.activePage = this.page;
  }

  get range(): (number | typeof DOTS)[] {
    const totalPageNumbers = this.siblings * 2 + 3 + this.boundaries * 2;
    if (totalPageNumbers >= this._total) {
      return range(1, this._total);
    }
    const leftSiblingIndex = Math.max(
      this.activePage - this.siblings,
      this.boundaries
    );

    const rightSiblingIndex = Math.min(
      this.activePage + this.siblings,
      this._total - this.boundaries
    );

    const shouldShowLeftDots = leftSiblingIndex > this.boundaries + 2;
    const shouldShowRightDots =
      rightSiblingIndex < this._total - (this.boundaries + 1);

    if (!shouldShowLeftDots && shouldShowRightDots) {
      const leftItemCount = this.siblings * 2 + this.boundaries + 2;
      return [
        ...range(1, leftItemCount),
        DOTS,
        ...range(this._total - (this.boundaries - 1), this._total),
      ];
    }

    if (shouldShowLeftDots && !shouldShowRightDots) {
      const rightItemCount = this.boundaries + 1 + 2 * this.siblings;
      return [
        ...range(1, this.boundaries),
        DOTS,
        ...range(this._total - rightItemCount, this._total),
      ];
    }

    return [
      ...range(1, this.boundaries),
      DOTS,
      ...range(leftSiblingIndex, rightSiblingIndex),
      DOTS,
      ...range(this._total - this.boundaries + 1, this._total),
    ];
  }

  private _setActivePage(page: number) {
    this.activePage = page;
    if (this.onChange) {
      this.onChange(page);
    }
  }

  setPage(page: number) {
    if (page < 1) {
      this._setActivePage(1);
      return;
    }
    if (page > this._total) {
      this._setActivePage(this._total);
      return;
    }
    this._setActivePage(page);
  }

  next() {
    this.setPage(this.activePage + 1);
  }

  prev() {
    this.setPage(this.activePage - 1);
  }

  first() {
    this.setPage(1);
  }

  last() {
    this.setPage(this._total);
  }
}

Example

License

This project is licensed under the MIT License.