2018-09-14 admin


什么是abend,Throw an error if there is an error.


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For when there’s nothing better to do than panic.

function abend (error) {
    if (error) {
        throw error
        setImmediate(function () { throw error })

Abend’s promise: I will unwind your stack and crash your program if it’s the last thing I do. It defeats any and all naive attempts to catch exceptions.

Abend is part of the Cadence Universe.

I use Abend to terminate the asynchronous stacks I create with Cadence. Cadence has robust asynchronous try/catch error handling.

Every program that is built around error-first callbacks has that one final callback that can’t do anything with the error. If that error is thrown it should not be caught.

If you are using Cadence, it won’t be caught, because Cadence uses a trampoline to invoke its user-specified program logic. It bounces user functions on the trampoline, then it calls it’s callback directly. There is no try/catch block enveloping the callback.

If you use Callback, and you through an exception, it will do the right thing.

However, we’re all trying to figure out this single threaded callback oriented environment, so when using other libraries you’re often using an ad-hoc asynchronous error handling strategy for each. There are times when your panicked exception is caught by these libraries and re-routed to someone’s notion of an error handler. Basically, as you add NPM modules to your project, the likelihood of your adding a poorly implemented and undocumented implementation of 'uncaughtException` approaches zero.

When using Cadence and its libraries, the handling of exceptions follow strict rules. They are caught within Cadence steps, but never caught after a Cadence function calls the callback it was given. Cadence is robust in handling exceptins, but never handles exceptions that where not meant for it.

That’s why this library exists. I use it in every significant project. It is the end of the line for all my Node.js programs.

Ed: Added copy that is not as good as the copy that is already here.


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