'use strict';
// Run and see random order
let count = 0;
console.log('start');
readConfig('myConfig', callbackCheck);
selectFromDb('select * from cities', callbackCheck);
getHttpPage('http://kpi.ua', callbackCheck);
readFile('README.md', callbackCheck);
console.log('end');
function callbackCheck() {
if (++count === 4) {
console.log('All done!');
}
}
// Emulate Asynchronous calls
function wrapAsync(callback) {
setTimeout(callback, Math.floor((Math.random() * 1000)));
}
// Asynchronous functions
function readConfig(name, callback) {
wrapAsync(() => {
console.log('(1) config loaded');
callback({ name });
});
}
function selectFromDb(query, callback) {
wrapAsync(() => {
console.log('(2) SQL query executed');
callback([ { name: 'Kiev' }, { name: 'Roma' } ]);
});
}
function getHttpPage(url, callback) {
wrapAsync(() => {
console.log('(3) Page retrieved');
callback('<html>Some archaic web here</html>');
});
}
function readFile(path, callback) {
wrapAsync(() => {
console.log('(4) Readme file loaded');
callback('file content');
});
}