Wanted to print console.log in sync - * every second print console in sync one by one
Output should be
start a 3 second timer
3 second remaining
2 second remaining
1 second remaining
after 3 second timer, start a 5 second timer
5 second remaining
4 second remaining
3 second remaining
2 second remaining
1 second remaining
both timers done!
Timer done!
function main() {
console.log('start a 3 second timer');
printTimer(3, () => {
console.log('after 3 second timer, start a 5 second timer');
printTimer(5, () => {
console.log("both timers done!");
});
});
}
main();
function printTimer(n, callback) {
for (let i = 0; i < n; i++) {
setTimeout(()=> console.log(`${n - i} seconds remaining`));
}
}
setTimeout(() => console.log('timer done!'))
callback()
}
I am new to JS and wanted to know how can we get such console.logs Thank you in advance
Solution:
function main() {
console.log('start a 3 second timer');
printTimer(3, () => {
console.log('after 3 second timer, start a 5 second timer');
printTimer(5, () => {
console.log("both timers done!");
console.log("Timer done!")
});
});
}
main();
async function printTimer(n, callback) {
const waitForMilliseconds = ms => new Promise(resolve => setTimeout(resolve, ms))
for (let i = 0; i < n; i++) {
console.log(`${n - i} seconds remaining`)
await waitForMilliseconds(1000)
}
callback()
}Instead of nesting your functions and iterating over setTimeouts create a function that returns a promise, and inside that promise use a setTimeout to log the numbers to the console. If you use async/await you can then just wait for each promise to resolve.
function timer(n) {
return new Promise((res, rej) => {
// `loop` accepts an argument `i` which is the
// initial value of n, but which gets reduced on
// each iteration
function loop(i) {
// If `i` reaches zero pass back the resolve value
if (i === 0) {
res('Done');
// Otherwise log the current value of `i`
// and call the loop function again reducing
// the value of `i`
} else {
console.log(`${i} seconds remaining.`);
setTimeout(loop, 1000, --i);
}
}
// Pass in the number, and start the loop
loop(n);
});
}
// Now just `await` the response from the promises
(async () => {
console.log('Start a 3 second timer');
console.log(await timer(3));
console.log('After 3 second timer, start a 5 second timer');
console.log(await timer(5));
console.log('Both timers done.');
})();