Promise statuses ​

const x = new Promise(resolve, reject) {
	[...]
}

x.then(result => { console.log(result) }, error => { console.log(error)}) // it still returns a promise to be handled by `catch`

// or
x.then(...).catch(...)

catch handles the error thrown by then function, not by Promise itself. If we won't handle the Promise error in then, it will be passed to catch.

In other words: catch catches all previously unhandled errors in the chain (Promises can be chained)

Promise.all(array) ​

Awaits all the promises in the array and returns the array of values of those promises. Is rejected if any of the passed promises is rejected.

Promise.race(array) ​

Returns the value of the promise that resolved first. Is rejected only if one of the promises will reject before any other of promises resolve.

Useful for timeout to any promise. We can just pass another promise that will throw an exception after the timeout is reached.

💡catch ​

catch returns another Promise with the status of... resolved, lol. If the Promise value is assigned to the variable, and catch returns this value, then the variable will have this value. Quite wat, if you ask me.

Resources ​

• Async and Await
• Promise @ MDN
• Using Promises @ MDN