SheetJS Change Header names to dynamic - sheetjs

Question

I am trying to change the header names in sheetJS to something I recieve from the form. Here is my form submit function:
onFormSubmit() {
const fileReader = new FileReader();
const solution = 'testsolution'; // normally i get this from a form input
fileReader.onload = (e) => {
this.arrayBuffer = fileReader.result;
const data = new Uint8Array(this.arrayBuffer);
const arr = [];
for (let i = 0; i != data.length; ++i) arr[i] = String.fromCharCode(data[i]);
const bstr = arr.join('');
const workbook = XLSX.read(bstr, {type: 'binary'});
const first_sheet_name = workbook.SheetNames[0];
const worksheet = workbook.Sheets[first_sheet_name];
// change the column names to match entity
const records = XLSX.utils.sheet_to_json(worksheet, {raw: true});
console.log('records - ', records);
};
fileReader.readAsArrayBuffer(this.file);
}
currently for example my headers come in like this:
AltId, FirstName, LastName
And I want them to end up like this with 'testsolution' apended with underscore and lowercase
testsolution_altid, testsolution_firstname, testsolution_lastname
NOTE: Header names may change depending on what sheet is uploaded. For example the next sheet uploaded may contain headers:
AltId, Address1, Address2, City, State
And should end up like
testsolution_altid, testsolution_address1, testsolution_address2, testsolution_city, testsolution_state
Any help would be appriciated!

Answer 1

I ended up doing it like this if it helps anyone else:
// change the column names to match entity
const newHeaders = [];
const columnCount = XLSX.utils.decode_range(ws['!ref']).e.c +1;
console.log(columnCount);
for (let i = 0; i < columnCount; ++i) {
newHeaders[i] = solution+'_'+ ws[`${XLSX.utils.encode_col(i)}1`].v.toLowerCase();
// console.log(header[i]);
}
// console.log(newHeaders);