json2csv | command line tool to convert json to csv | CSV Processing library

I'm using json2csv v5.0.6 for a small project and I wanted to format some values using custom formatters so I get a clean CSV file.

However, I can't seem to make the formatters work. I have one number formatter and one string formatter that are supposed to be called upon parsing. Here's a sample test file that reproduces this behaviour, with two simple formatters:

I would like to put all jq filters inside a text file and use the jq -L option to execute the filters. However, I can't get this simple thing working.

Inside my sample2.json file, I have:

I am doing some really simple testing regarding reading csv files into a json format using the csvtojson node module, I used the code below as a template

I am facing some issues with appending data into csv file.

First the data is retrieved from a webpage using cheerio. But when I want to execute a function to check whether the file exists/accessible, I cannot run the function in the class. Even when I pass the data to the third function writeDataIntoFile(), it still shows the same error.

Here is the code:

I am creating a project in Node JS and Typescript in which I want to download a CSV with the information that an API contains in JSON format. Given the url http://localhost:3000/?api=api1, I have to read the JSON related to api1.

I have added the modules that I have seen that are necessary but I cannot download the CSV from an external JSON by url.

This is my controller:

I have a project in Node JS in which I want to export the data contained in the database in Mongo DB in a CSV file through a button in the view (index.ejs). I am using mongoose for the connection to the database and to export the data to the CSV I am trying to use json-2-csv.

In the button I have added a url to be able to call that url through the button and that the json-2-csv function responds to that url but I don't know how to do it or if it is the best way.

This is my app.js:

I have put together the below code that creates a CSV called example.csv, using the json2csv library.

I would prefer to not have to save down and store the CSV file before it is passed to the front end to be downloaded.

I can't seem to figure out how to stream or pipe the file to the front end, without saving it first.

How to take the output CSV file of the json2csv library and send it straight tot he front end?

Some of my code

I wanted to scrape a website's data, so I tried it using cheerio npm package
The selector works perfectly fine in chrome dev tools

I am new to nodejs and trying to write this web scraper where I am getting the following errors. It asks to return promise however I tried but nothing works out. Not sure if I am using the right packages. Promises in async is quite difficult to understand for me at this point. Any explanation along with the code will be really apprciated.