Is it possible, within a new Promise((resolve, reject) => { //here })
block to tell whether a promise has a catch handler (or error handler, more generally, as for .then(..., errorHandler)
clauses)?
I'd like to print an error message in case the promise hasn't, but otherwise don't.
You may not be able to check in the promise scope, but you could add a listener for a un-handled rejection in the browser. A event will be emitted if there was a un-hanlded promise.
Browser
window.addEventListener('unhandledrejection', function(event) {
// event.promise error handling
});
Node
process.on('unhandledRejection', function(err, promise) {
// promise error handling
});
https://developer.mozilla.org/en-US/docs/Web/API/Window/onunhandledrejection https://thecodebarbarian.com/unhandled-promise-rejections-in-node.js.html
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