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xfarrow 2024-07-04 12:13:47 +02:00
parent 11d149edc9
commit 04e200e406
3 changed files with 42 additions and 35 deletions
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72
async-await/1_promises.js
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@ -10,43 +10,49 @@
A Promise can be in one of these three states:
- Pending (the operation is being processed)
- Fullfilled (the operation has completed successfully)
- Rejected
- Fullfilled (the operation has completed successfully, resolve has been called)
- Rejected (the operation has not completed successfully, reject has been called)
*/
const promise = new Promise(function (resolve, reject) {
setTimeout(() => resolve('done'), 500);
});
setTimeout(() => resolve('done'), 5000);
});
/*
The first argument of .then is a function that runs when the promise is resolved and receives the result.
The second argument of .then is a function that runs when the promise is rejected and receives the error.
The function passed to "then()" is put in the event loop queue!
*/
promise.then(
result => console.log('The operation was successful. It returned ' + result),
error => console.log('The operation was not successful: ' + error)
);
/*
The first argument of .then is a function that runs when the promise is resolved and receives the result.
The second argument of .then is a function that runs when the promise is rejected and receives the error.
The function passed to "then()" is put in the event loop queue!
*/
promise.then(
result => console.log('The operation was successful. It returned ' + result),
error => console.log('The operation was not successful: ' + error)
);
/*
Or we can pass only one argument if we're interested only in a positive result
*/
promise.then(
result => console.log('The operation was successful. It returned ' + result)
);
/*
Or we can pass only one argument if we're interested only in a positive result
*/
promise.then(
result => console.log('The operation was successful. It returned ' + result)
);
/*
Or we can pass only one argument to the method "catch" if we're interested
in negative results only.
/*
Or we can pass only one argument to the method "catch" if we're interested
in negative results only.
promise.catch internally just calls promise.then(null, f)
*/
promise.catch(
error => console.log(error)
);
promise.catch internally just calls promise.then(null, f)
*/
promise.catch(
error => console.log(error)
);
/*
finally gets always called
*/
promise.finally(
() => console.log('The execution has terminated. Bye')
);
/*
finally gets always called
*/
promise.finally(
() => console.log('The execution has terminated. Bye')
);
/*
This line is used to demonstrate that the code within "then, catch, etc."
is in the event loop, as this is the first line getting executed.
*/
console.log("Last line");

0
async-await/3_promise-chaining.js → async-await/2_promise-chaining.js
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5
async-await/event-loop.txt
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@ -1,3 +1,4 @@
JavaScript is single-threaded (but note that NodeJS is not entirely single-threaded, as it internally mantains a thread pool), but it can still take advantage of asynchronous programming.
JavaScript is single-threaded (but note that NodeJS is not entirely single-threaded, as it internally mantains a thread
pool), but it can still take advantage of asynchronous programming.
The Event Loop, which is a JavaScript construct that completes a new task while waiting for another
The Event Loop, which is a JavaScript construct that completes a new task while waiting for another.