Pass Parameters Besides URL in Next JS in Client Side API Fetch - rest

Question

I've been working on calling an internal GetCompanies API through the website client side.
So far I made attempts like this based on search results and documentation
// const fetcher = (includeFiles, folderLocation, SharePointCreds) => fetch(includeFiles, folderLocation, SharePointCreds).then(res => res.json());
// const { data, error } = useSWR('http://localhost:55419/api/SharePoint/GetCompanies', fetcher);
// if (error) return <div>failed to load</div>
// if (!data) return <div>loading...</div>
// render data
//return <div>hello {data}!</div>
useEffect((includeFiles, folderLocation, SharePointCreds) => {
fetch('http://localhost:55419/api/SharePoint/GetCompanies', includeFiles, folderLocation, { method: "POST", body: SharePointCreds})
.then((res) => res.json())
.then((data) => {
console.log("data is ", data)
})
}, [])
if (isLoading) return <p>Loading...</p>
// async function GetCompanies(includeFiles, folderLocation, SharePointCreds){
// const res = await fetch('http://localhost:55419/api/SharePoint/GetCompanies');
// const companies = await res.json();
// }
// return (
// <div>
// <p>{data}</p>
// </div>
// )
corresponding to an API call which works when we test it in Swagger
And I got generic error messages like TypeError: Failed to fetch
I guess the error is in how I pass in includeFiles and folderLocation since I haven't yet found documentation or search results for how to pass in parameters besides the URL, though I could be wrong.
I define all the arguments earlier in the portfolio component for now.
Do you see how else I should pass in includeFiles and folderLocation?
Also, please be kind because I'm learning and doing my best and I've worked on this for a few hours already.