fetching inside express server - fetch is not defined

Question

I am trying to get a long lived access token from facebook... according to the documentation, I need to fetch from the server side for security. If I fetch from the client side it works fine - but I should follow the guidelines.. Here is what I am doing - can you tell me why I get the server side error "Reference error: fetch is not defined"?

First I created a route from the front end to request the long lived token. To get the long lived token I need to use the short lived token so I send the short lived token in the req params. The variable userAccessTokenShort is valid and defined.

const newLongLivedUserAccessToken = await fetch(`/api/autoquotegenerators/longLivedUserToken/${userAccessTokenShort}`, {
            method: 'GET',
            headers: {
                Authorization: `Bearer ${token}`,
                "Content-Type": "application/json; charset=UTF-8",
            },
        })
        const newLongUserTokenRes = await newLongLivedUserAccessToken.json()
        console.log(newLongUserTokenRes)

Then, on my express server, I made a route that handles the fetch request to the Facebook Graph API. This is where I get the reference error.

//Get Long Lived User Access Token on Backend /express route
router.get('/longLivedUserToken/:shortLived', (req, res) => {
    try {
        const getLongToken = fetch(`https://graph.facebook.com/v7.0/oauth/access_token?grant_type=fb_exchange_token&client_id=#############&client_secret=################&fb_exchange_token=${req.params.shortLived}`)
        .then(token => res.send(token))

    } catch (error) {
        console.log(error)
    }
})

If all goes well, the new token should be sent back to the client.

Thanks for your help!

Answer 1

There is no fetch() function built into node.js. If you want something that looks pretty much like fetch() in the browser, you can look at the node-fetch module in NPM.

Or, there are lots of modules you can choose from in node.js. My favorite is got().

FYI, the built-in interface for fetching http requests is http.request() or http.get(), but they are lower level and require more lines of code to do something simple than any of the above named modules.