Re: Suggested Enhancement to ecmascript

Fri, 11 May 2018 15:26:17 -0700

What would be nice is if we could have a good way of watching a variable. Maybe a built in way to create a custom event emitter.

Sebastian Malton

Sent: May 11, 2018 6:05 PM
Subject: Re: Suggested Enhancement to ecmascript

I agree, Promises easily allow you to do this. Even if you wanted to 'wait' on an event, you can either.

1. Use EventEmitter and simply have an 'on' handler
2. Create a promise and pass the resolve function to whatever js doing the work, and `await` on the promise itself 

You can also wrap an event emitter callback with a promise, oe use something like RxJS for Observables. So many possibilities.

On Fri, May 11, 2018, 4:56 PM Michał Wadas <[email protected]> wrote:
What's wrong with async functions and
await Promise.all([a, b, c])
?

On Fri, May 11, 2018 at 11:14 PM, Matthew Tedder <[email protected]> wrote:

wait for ( condition );

Stop executing statements until the condition evaluates to true.  To implement this, freeze the instance of the function in, add a hook to each variable in the condition so that when its value is written to, the condition is re-evaluated.

This will greatly increase the clarity and reduce coding needed for operations with many asynchronous calls and any with callbacks using arrow functions..  E.g.,

let a = false;
let b = 5;
let c = 'oranges';
doSomethenWhenever( () => { a = true; }
doAnotherThingWhenever( () => { b = 16; }
DoYetAnotherThing( () => { c = 'apples'; }
wait for ( a && b > 10 && c !== 'oranges' );
console.log('Conditions are met!');


--
Matthew C. Tedder
HyperConversal, Inc.
Desk: 352-381-7142 / Cell: 509-432-5520

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