UNPKG

@sota1235/parse-link-header-ts

Version:

Parses a link header and returns paging information for each contained link.

54 lines (53 loc) 1.44 kB
const PARSE_LINK_HEADER_MAXLEN = 2000; function hasRel(link) { if (link === null) { return false; } return link.rel != null; } function intoRels(acc, link) { function splitRel(rel) { acc[rel] = { ...link, ...{ rel } }; } link.rel.split(/\s+/).forEach(splitRel); return acc; } function createObjects(acc, p) { const m = p.match(/\s*(.+)\s*=\s*"?([^"]+)"?/); if (m) acc[m[1]] = m[2]; return acc; } function parseLink(link) { const m = link.match(/<?([^>]*)>(.*)/); if (m === null) { throw new Error('Invalid link header'); } const linkUrl = m[1]; const parts = m[2].split(';'); const parsedUrl = new URL(linkUrl); const qry = {}; for (const [key, value] of parsedUrl.searchParams) { qry[key] = value; } parts.shift(); let info = parts.reduce(createObjects, {}); info = { ...qry, ...info, url: linkUrl }; return info; } function checkHeader(linkHeader) { if (linkHeader.length > PARSE_LINK_HEADER_MAXLEN) { throw new Error(`Input string too long, it should be under ${PARSE_LINK_HEADER_MAXLEN} characters.`); } } export default function (linkHeader) { if (linkHeader === '') { throw new Error('linkHeader is empty'); } checkHeader(linkHeader); return linkHeader .split(/,\s*</) .map(parseLink) .filter(hasRel) .reduce(intoRels, {}); }