Using the built in NodeJs fetch client does not have the same return type.

  • I am upgrading my app and going to use the built in http client 'fetch'. I have been using the request library that is now deprecated. I am having an issue with what 'fetch' returns from JsReport. I am getting a string so when 'response.json()''' is called I get error 'Unexpected token '%', "%PDF-1.6\n%"... is not valid JSON'. When I call the same url with 'request' I get an object. It seems like 'fetch' only returns the content of the body property. Is anyone having a similar issue?

    request code:

        const promise = new Promise<any>((resolve, reject) => {
          const options = {
            json: data,
            uri: ''
          post(options, (err, result) => {
            if (err) {
              return reject(err);
        return promise;

    fetch code:

        try {
          const response = await fetch('', {
            method: 'POST',
            headers: {
              'Accept': 'application/json',
              'Content-Type': 'application/json'
          if (response.ok && response.body) {
            const body = await response.json(); //error occurs here
            return body;
          } else {
            throw new Error('Failed to fetch the report');
        } catch (error: any) {
          return Promise.resolve(error);

  • The response is a binary stream containing the report content and not a json, therefore the response.json won't work and fail on json parsing error.

    I don't know what you want to do with the output afterward, but you can use for example await response.arrayBuffer()

  • @admin I think I get it now. I am able to recreate what my client was expecting with the following code. It needed a body property with the data and a headers property with a permanent-link property. Thanks

    const body = await response.text();
    const permanentLink = await response.headers.get('permanent-link');
    return {data:{body,headers:{'permanent-link':permanentLink}}};

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