react-native-fetch-charset-issue.js

// RN's fetch seems to not handling responses with other charsets correctly like Node.js does
// eg. the following link returns content-type: "text/html; charset=ISO-8859-1" 
// https://www.corriere.it/cronache/20_marzo_13/coronavirus-ultimi-aggiornamenti-dall-italia-mondo-d4c07168-64f4-11ea-ac89-181bb7c2e00e.shtml
// response.text() resolves to undefined
const src = await fetch(url)
  .then(response => {
    const charset = (response.headers.get("content-type") || "").split(
      "charset="
    )[1];
    if (!charset || charset.toLowerCase() === "utf-8") {
      return response.text();
    }
    return response.blob().then(blob => [blob, charset]);
  })
  .then(result => {
    if (Array.isArray(result)) {
      let resolve, reject;
      const readingPromise = new Promise((res, rej) => {
        resolve = res;
        reject = rej;
      });
      const fileReader = new FileReader();
      fileReader.addEventListener("loadend", result => {
        resolve(fileReader.result);
      });
      fileReader.addEventListener("error", reject);
      fileReader.addEventListener("abort", reject);
      const [blob, charset] = result;
      fileReader.readAsText(blob, charset);
      return readingPromise;
    }
    return result;
  });