TypeScript import node "fs" module

import_fs.ts

import * as fs from 'fs';
import * as https from 'https';

function afterWrite(err): void {
    if (err) {
        throw new Error('Failed to write to file.');
    }
}

function writeSomeData(err, fd): void {
    if (err) {
        throw new Error('Failed to open file for writing');
    } else {
        console.log('the file opened');
        fs.write(fd, 'some data to write', afterWrite);
    }
}

function afterUnlink(err): void {
    if (err) {
        throw new Error('Failed to unlink the file');
    } else {
        fs.open('./testfile', 'w', writeSomeData);
    }
}

function openOrUnlink(err, stats): void {
    if (err && !stats) {
        fs.open('./testfile', 'w', writeSomeData);
    } else if (err) {
        throw new Error('Stats exist but error raised.');
    } else {
        console.log('file exists unlinking....');
        fs.unlink('./testfile', afterUnlink);
    }
}

fs.stat('./testfile', openOrUnlink);


https.get('https://www.pizzapatron.com', (message) => {
    console.log('httpVersion = ' + message.httpVersion);
    let buffer = '';
    message.on('data', (chunk) => {
        buffer += chunk;
    });
    message.on('end', () => {
        console.log('data = ' + buffer);
    });
});