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    Catch Errors in a JavaScript Promise Chain with Promise.prototype.catch()


    The Promise.prototype.then() method accepts two callbacks as parameters, onFulfilled and onRejected:

    • If the promise is fulfilled, onFulfilled will be called.
    • If the promise is rejected, onRejected will be called.
    • If the promise never settles (that is, stays pending forever), neither one will be called.

    If you want to register a handler for rejected promises only, you can use the Promise.prototype.catch() method: .catch(onRejected) behaves the same as .then(undefined, onRejected).