Navigating the contents of the text file using TypeScript

Question

Navigating the contents of the text file using TypeScript

After locating the file flight.txt, I have obtained the following flight information:

1 DFW BOM 2016-05-20 12:20 2016-05-21 02:40 1084.00 JetAirways 100
2 DFW DEL 2016-04-24 17:15 2016-04-25 07:20 1234.00 Lufthansa 100
3 DFW FRA 2016-06-05 13:30 2016-06-05 03:32 674.00 AmericanAirlines 100

The provided code demonstrates how to read a file in typescript:

 populateFlightList() {
   let data = fs.readFileSync('flight.txt').toString('utf-8'); {
        let textByLine = data.split("\n")
        console.log(textByLine);

    };

I am now looking to iterate through the file, extract the necessary data and convert it into flight objects by creating new objects and adding them to an array list.

   try {
        Scanner fin = new Scanner(file);                
        while(fin.hasNext()) {
          int number = fin.nextInt();                 // Flight number
          String from = fin.next();                   // Departure airport
          String to = fin.next();                     // Arrival airport
    }**Code in Java**

Is there a similar way to achieve this functionality in TypeScript?

javascript typescript typescript-typings typescript2.0

Answer 1

Answer №1

If you want to read data from a file one line at a time, you can utilize the readline module in Node.js. However, keep in mind that parsing the data will require manual effort. Here's a sample code snippet:

import * as fs from 'fs';
import * as rd from 'readline'

var reader = rd.createInterface(fs.createReadStream("W:\\tmp\\stack\\2\\data.txt"))

var data: Array<{ number: number; from: string; to: string}> = [];
reader.on("line", (l: string) => {
    var tokens = l.split(' ');
    var nr= parseInt(tokens[0]);
    var from = tokens[1];
    var to = tokens[2]
    console.log(`nr: ${nr} from ${from} to ${to}`);
    data.push({
        number: nr, from, to
    });
})
console.log(`The data array is currently empty because data has not been read yet: ${data.length}` );

reader.on("close", ()=> {
    console.log(`Data has been successfully read. Total entries: ${data.length}` );
    data.forEach(element => {
        console.log(`nr: ${element.number} from ${element.from} to ${element.to}`)
    });
})

The line event will be triggered for each line of the file being read. The close event, on the other hand, will signal that the entire file has been read and closed, making the complete dataset available for processing. Remember, you are building up your data set one entry at a time every time the line event occurs.

To learn more about the readline module, refer to the official documentation.

Answer 2

If you want to read data from a file one line at a time, you can utilize the readline module in Node.js. However, keep in mind that parsing the data will require manual effort. Here's a sample code snippet:

import * as fs from 'fs';
import * as rd from 'readline'

var reader = rd.createInterface(fs.createReadStream("W:\\tmp\\stack\\2\\data.txt"))

var data: Array<{ number: number; from: string; to: string}> = [];
reader.on("line", (l: string) => {
    var tokens = l.split(' ');
    var nr= parseInt(tokens[0]);
    var from = tokens[1];
    var to = tokens[2]
    console.log(`nr: ${nr} from ${from} to ${to}`);
    data.push({
        number: nr, from, to
    });
})
console.log(`The data array is currently empty because data has not been read yet: ${data.length}` );

reader.on("close", ()=> {
    console.log(`Data has been successfully read. Total entries: ${data.length}` );
    data.forEach(element => {
        console.log(`nr: ${element.number} from ${element.from} to ${element.to}`)
    });
})

The line event will be triggered for each line of the file being read. The close event, on the other hand, will signal that the entire file has been read and closed, making the complete dataset available for processing. Remember, you are building up your data set one entry at a time every time the line event occurs.

To learn more about the readline module, refer to the official documentation.

Navigating the contents of the text file using TypeScript

Answer №1

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