How can I save a file (in node.js) from memory to a specific location on the disk?

I'm trying to save a file to a specific location on the server disk (using multer), but this location name is related to data i receive in request along with file.

I came to conclusion that I can save file in memory, and later (after some other part of code will complete, and i will have my location name generated) I will save that file to disk space. And this is where i stuck - how can I save file in node.js from object in memory to specific disk location?

This is object that i have saved in memory:

{ fieldname: 'file',
  originalname: '20190221_171825.jpg',
  encoding: '7bit',
  mimetype: 'image/jpeg',
  buffer:
   ,
  size: 5173060 }

Answer

TL:DR via fs module

const fs = require('fs');
const data = { fieldname: 'file',
  originalname: '20190221_171825.jpg',
  encoding: '7bit',
  mimetype: 'image/jpeg',
  buffer:
   ,
  size: 5173060 };

fs.writeFile("path/to/file", data, function(err) {
    if(err) {
        return console.log(err);
    }
    console.log("The file was saved!");
}); 

But to be honest, you should check other relevant questions before asking a new one here.