astro/dist/core/render/paginate.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

import { AstroError, AstroErrorData } from "../errors/index.js";
import { joinPaths } from "../path.js";
import { getRouteGenerator } from "../routing/generator.js";
export function generatePaginateFunction(routeMatch, base, trailingSlash) {
	return function paginateUtility(data, args = {}) {
		const generate = getRouteGenerator(routeMatch.segments, trailingSlash);
		let { pageSize: _pageSize, params: _params, props: _props, format: _format } = args;
		const pageSize = _pageSize || 10;
		const paramName = "page";
		const additionalParams = _params || {};
		const additionalProps = _props || {};
		const formatUrl = _format || ((url) => url);
		let includesFirstPageNumber;
		if (routeMatch.params.includes(`...${paramName}`)) {
			includesFirstPageNumber = false;
		} else if (routeMatch.params.includes(`${paramName}`)) {
			includesFirstPageNumber = true;
		} else {
			throw new AstroError({
				...AstroErrorData.PageNumberParamNotFound,
				message: AstroErrorData.PageNumberParamNotFound.message(paramName)
			});
		}
		const lastPage = Math.max(1, Math.ceil(data.length / pageSize));
		const result = [...Array(lastPage).keys()].map((num) => {
			const pageNum = num + 1;
			const start = pageSize === Number.POSITIVE_INFINITY ? 0 : (pageNum - 1) * pageSize;
			const end = Math.min(start + pageSize, data.length);
			const params = {
				...additionalParams,
				[paramName]: includesFirstPageNumber || pageNum > 1 ? String(pageNum) : undefined
			};
			const current = formatUrl(addRouteBase(generate({ ...params }), base));
			const next = pageNum === lastPage ? undefined : formatUrl(addRouteBase(generate({
				...params,
				page: String(pageNum + 1)
			}), base));
			const prev = pageNum === 1 ? undefined : formatUrl(addRouteBase(generate({
				...params,
				page: !includesFirstPageNumber && pageNum - 1 === 1 ? undefined : String(pageNum - 1)
			}), base));
			const first = pageNum === 1 ? undefined : formatUrl(addRouteBase(generate({
				...params,
				page: includesFirstPageNumber ? "1" : undefined
			}), base));
			const last = pageNum === lastPage ? undefined : formatUrl(addRouteBase(generate({
				...params,
				page: String(lastPage)
			}), base));
			return {
				params,
				props: {
					...additionalProps,
					page: {
						data: data.slice(start, end),
						start,
						end: end - 1,
						size: pageSize,
						total: data.length,
						currentPage: pageNum,
						lastPage,
						url: {
							current,
							next,
							prev,
							first,
							last
						}
					}
				}
			};
		});
		return result;
	};
}
function addRouteBase(route, base) {
	// `routeMatch.generate` avoids appending `/`
	// unless `trailingSlash: 'always'` is configured.
	// This means an empty string is possible for the index route.
	let routeWithBase = joinPaths(base, route);
	if (routeWithBase === "") routeWithBase = "/";
	return routeWithBase;
}