I get undefined from fetch only on chrome, while it works on firefox.

// content script
async function fetchAPI(link, init = {}) {

    let res = await chrome.runtime.sendMessage({
        url: link,
        config: init
    })

    return res;
}

fetchAPI(`some link`);

// background script
chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
    console.log(request);

    return new Promise((resolve) => {
        fetch(request.url, request.config)
            .then(res => {
                res.json()
                    .then(value => {
                        resolve(value);
                    });
            });
    });
});

Sorry about the messy background script code. I don't think I have much more to explain.