CODEWITHSUNDEEP
javascript
ThomasReggi
ThomasReggi

Reputation: 59365

Is there a simpler way to do a one-line try without catch?

When I do something like this:

let resolved = null;
try {
    resolved = require.resolve(modulePath)
} catch (e) {

}

I am wondering if there's a shorter syntax something like:

let resolved = null;
try resolved = require.resolve(modulePath)

Is there any way to forgive this line without opening up a catch block?

There's something like this but I'm looking for something more natural:

function t (fn, def) {
    let resolved = def;
    try {
        resolved = fn()
    } catch (e) {

    }
    return resolved;
}

Upvotes: 6

Views: 1302

Answers (3)

Matías Fidemraizer
Matías Fidemraizer

Reputation: 64923

As other answerers have already pointed out, you either need to provide catch or finally.

BTW, what's wrong with implementing a high-order function?

const valueOrNull = f => {
  try {
    return f ()
  } catch (e) {
    return null
  }
}

const output1 = valueOrNull (() => { throw Error () })
const output2 = valueOrNull (() => "hello world")

console.log ('output1', output1)
console.log ('output2', output2)

Upvotes: 0

ruakh
ruakh

Reputation: 183321

No; it's intentional that JavaScript try-blocks must have either catch or finally. From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch#Description:

The try statement consists of a try block, which contains one or more statements. {} must always be used, even for single statements. At least one catch clause, or a finally clause, must be present.

(And note that try { ... } finally { }, with no catch, does the opposite of what you want: you want everything to be caught and swallowed, whereas try { ... } finally { } doesn't catch anything.)

In your case, I think the best way to write it is:

let resolved;
try {
    resolved = require.resolve(modulePath);
} catch (e) {
    resolved = null;
}

which makes clear that resolved == null is the error-case.

(Better yet — add some logic to make sure that the exception you've caught is really the one you're expecting. You probably don't want to silently swallow exceptions that result from unintended bugs!)

Upvotes: 5

Laurens Deprost
Laurens Deprost

Reputation: 1691

Is there any way to forgive this line without opening up a catch block?

Yes, if you implement a finally clause.
Other than that, no.
A try is always accompanied by either a catch or a finally.

Upvotes: 2

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