How can I read lines from .txt file, save in array, and print array asynchronously?

Question

I have a .txt file that I want to save in a JS array and then console.log that array. I know from this answer how to read the file into an array, but the problem is when I try to console.log the array, it logs it as empty. Here's my code:

const fs = require('fs')
let arr = []
let fileReader = async () => {
  await fs.readFile('temp.txt', (err, data) => { 
    if (err) throw err; 
    console.log(data.toString()); // confirming that line is successfully read
    arr.push(data.toString());
  })
  console.log(arr)
}
fileReader()

I figured that the console.log would wait until the array had finished being populated in fs.readFile(), and so it would print the populated array. Note that I console.log every line when it's read, in order to confirm that text is indeed being pushed to the array.

Does anyone know why this approach wouldn't work, or how I can do it differently? I want to stick with the asynchronous readFile rather than the synchronous readFileSync for now. Note that if I did want to do it synchronously, this code works:

const fs = require('fs')
let arr = fs.readFileSync("temp.txt").toString('utf-8').split("\n")
console.log(arr)

Answer 1

Once you have your file data after data.toString() you can split it by \n. For example:

let data = data.toString()
let data_rows_arr = data.split('\n') //defines a new line seperator.

for(row of data_rows_arr){
   //Do something with your rows
}

Hope that helped you :)