masto/dist/esm/adapters/config/merge-headers-init.js

Mastodon API client for JavaScript, TypeScript, Node.js, browsers

export const mergeHeadersInit = ([head, ...tail]) => {
    const headers = new Headers(head);
    for (const entry of tail) {
        for (const [key, value] of new Headers(entry).entries()) {
            headers.set(key, value);
        }
    }
    return headers;
};