radish/build/util/fetch.js

Radish is a React-based static site generator that outputs plain HTML and CSS.

import http from "http";
import https from "https";
export default function fetch(url) {
    return new Promise((resolve, reject) => {
        const lib = url.startsWith("https") ? https : http;
        lib.get(url, res => {
            if (!res.statusCode)
                return reject(new Error(`GET "${url}" returned no status.`));
            if ([301, 302, 307].includes(res.statusCode)) {
                if (!res.headers.location) {
                    const err = new Error(`GET "${url}" returned status ${res.statusCode} but no location header.`);
                    return reject(err);
                }
                return fetch(new URL(res.headers.location, url).toString())
                    .then(resolve)
                    .catch(reject);
            }
            if (res.statusCode === 200) {
                const chunks = [];
                res.on("data", chunk => chunks.push(chunk));
                res.on("end", () => resolve(Buffer.concat(chunks).toString()));
            }
            else
                reject(new Error(`GET ${url} returned status ${res.statusCode}`));
        });
    });
}