Upload PDF as binary data to SQL Server via NEXT.js app

Question

I am trying to solve this problem:

I am building an app in NEXT.js where users should upload certain documents (pdf,docx,etc.). I need to store those documents inside SQL Server as blobs. I do not know how should I pass data content of selected file to the API. I tried to use arrayBuffer or convert it to text and then cast as varbinary but without any success. I probably need completely different approach on this but was not able to find anything useful to my particular situation. Thanks in advance!

async function filesUpload(e) {
  e.preventDefault();
  const file = e.target.file.files[0];
  

  /** File validation */
  if (!file.type.startsWith("application/pdf")) {
    alert("Please select a valid document");
    return;
  }
  const buffer = await file.arrayBuffer();
  console.log(buffer)
  console.log({DATA: await file.text()})

  const endpoint = '/api/PostData/insertContractDoc';
    const options = {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json', 
      },
      body: JSON.stringify({DATA: await file.text()}),
    }

    //const response = await (await fetch(endpoint, options)).json()
  
  return
}

And this is my API endpoint:

const sql = require('mssql');
const configOBJ = require('../../../components/configSQL.js');

export default async function getAll(req,res){
    await sql.connect(configOBJ.confSQL).then(pool => { 
        console.log("insert into [CONTRACTDOCUMENTS] values(302,1,null,null,'adad',CAST("+ req.body.DATA+" AS VARBINARY(MAX)))")
        let querySTR = "insert into [CONTRACTDOCUMENTS] values(302,1,null,null,'adad',CAST("+ req.body.DATA+" AS VARBINARY(MAX)))"
        return pool.request().query(querySTR)
    }).then(result => {

        //console.log(result);
        return res.status(200).json(result);
    }).catch(err => {
        // ... error checks
        console.log(err);
        return res.status(500).send(err);
    })
}