I’d much rather see something more like C# 7’s throw expressions:
https://docs.microsoft.com/en-us/dotnet/articles/csharp/whats-new/csharp-7#throw-expressions
```js
// original example
fs.writeFile("message.txt", "Hello Node.js", err => err ? throw err :
console.log("The file has been saved.");
// better example
function choose(kind) {
return kind === 0 ? choseZero() : kind === 1 ? chooseOne() : throw new
Error("out of range");
}
```
Ron
From: es-discuss [mailto:[email protected]] On Behalf Of T.J.
Crowder
Sent: Tuesday, April 11, 2017 5:20 AM
To: Elie Rotenberg <[email protected]>
Cc: Нурбек <[email protected]>; es-discuss <[email protected]>
Subject: Re: throwif operator
I don't think we need a new keyword for this, both because of Elie's point
about handling it with a `throwif` function, and because Node's callback
pattern is a bit old-fashioned in the world of promises and async/await. Until
the Node API is updated to support promises natively, you can use one of the
various "promisifying" libs to promisify the API:
```js
const pfs = /*...promisified version of fs*/;
```
...and then:
```js
pfs.writeFile("message.txt", "Hello Node.js")
.then(() => console.log("The file has been saved."));
```
...and like your original code snippet, it will (on recent versions) terminate
Node if you don't handle the error.
Combined with `async`/`await`, it becomes even cleaner:
```js
await pfs.writeFile("message.txt", "Hello Node.js");
console.log("The file has been saved.");
```
(Of course, that has to be within an `async` function.)
-- T.J. Crowder
On Tue, Apr 11, 2017 at 1:15 PM, Elie Rotenberg
<[email protected]<mailto:[email protected]>> wrote:
const throwIf = (fn) => (err, ...args) => {
if(err) throw err;
return fn(...args);
};
...
fs.writeFile('message.txt', 'Hello Node.js', throwIf(() => console.log('The
file has been saved')));
No need to extend the language and preempt keywords with stuff you can very
easily implement in userland.
I'm not even convinced such a construct would be a good idea anyway to
encourage rethrowing errors without thinking if it can be handled locally.
On Tue, Apr 11, 2017 at 2:06 PM, Нурбек
<[email protected]<mailto:[email protected]>> wrote:
An example from node.js documentation:
fs.writeFile('message.txt', 'Hello Node.js', (err) => {
if (err) throw err;
console.log('The file has been saved!');
});
This looks like a common way to handle errors when the first parameter is an
instance of Error.
Yes, this line of code is short and easy to copy-paste.
But introducing something like this:
fs.writeFile('message.txt', 'Hello Node.js', (err) => {
throwif err;
console.log('The file has been saved!');
});
would make the code much cleaner and bring some sort of standart way to handle
such errors.
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