parse-link-header.js

export default function parseLinkHeader(link) {
    const parsed = [];
    const items = link.split(',');
    for (const item of items) {
        // https://tools.ietf.org/html/rfc5988#section-5
        const [rawUriReference, ...rawLinkParameters] = item.split(';');
        const trimmedUriReference = rawUriReference.trim();
        // eslint-disable-next-line @typescript-eslint/prefer-string-starts-ends-with
        if (trimmedUriReference[0] !== '<' || trimmedUriReference[trimmedUriReference.length - 1] !== '>') {
            throw new Error(`Invalid format of the Link header reference: ${trimmedUriReference}`);
        }
        const reference = trimmedUriReference.slice(1, -1);
        const parameters = {};
        if (rawLinkParameters.length === 0) {
            throw new Error(`Unexpected end of Link header parameters: ${rawLinkParameters.join(';')}`);
        }
        for (const rawParameter of rawLinkParameters) {
            const trimmedRawParameter = rawParameter.trim();
            const center = trimmedRawParameter.indexOf('=');
            if (center === -1) {
                throw new Error(`Failed to parse Link header: ${link}`);
            }
            const name = trimmedRawParameter.slice(0, center).trim();
            const value = trimmedRawParameter.slice(center + 1).trim();
            parameters[name] = value;
        }
        parsed.push({
            reference,
            parameters,
        });
    }
    return parsed;
}