Type Error in json2csv module

[rsgok]

Background Information

• Module Version: 3.10.0
• Node/Browser Version: ``

The issue I'm reporting is with:

• json2csv
• csv2json

I have...

• searched to see if an issue has already been reported.
• verified that my JSON/CSV data is valid (using something like http://jsonlint.com or https://csvlint.io/).
• tried upgrading to the latest version of json-2-csv (since the issue may already be fixed).

Expected Behavior

not have typescript error tip
use json-2-csv smoothly according to the docs

Actual Behavior

not as expected

Data Sample

CSV:

(or)

JSON:

Code Example

// Please include a simple example to replicate the issue
let converter = require('json-2-csv');
const convertRes = await converter.json2csvAsync(data, {
  excelBOM: true,
  keys: [{title: 'a', key: 'aa'}, 'bb']
});