I was wondering if there is a way to not specify the argument when doing a JS try/catch. Every time I try this though, the try/catch doesn't work.
The working version:
try{
//Breaking code
} catch(e){
//Nothing happens here
}
What I have in mind (No 'e'):
try{
//Breaking code
} catch(){
//Nothing happens here
}
In Node.js, this feature is called Optional Catch Binding and is supported since Node.js version 10.3, see https://node.green.
In Typescript, this is allowed since version 2.5.
The proposal is currently Stage 4, meaning that its implementation is finished and it is guaranteed to be included into the next version of the ECMAScript standard.
So this is a perfectly legitimate syntax now according to the standard if you are using Node.js or transpiling your browser code using Babel:
try {
} catch {
// No need for the `(error)` after `catch`!
}
esnext this syntax will be emitted, breaking browsers like Edge that don't support it. (I believe there's actually a merged PR to add this capability to Edge, but it was last year and still hasn't landed. I can't find the page I read this on in my history now...)This is an outdated answer. It no longer applies to the current version of JavaScript. See other answers for details.
You just can't. The spec says that there must always be an identifier inside parens after catch.
try {...} catch {...} (that is, omit the parens and the identifier). However, I would advise against it, as it can lead to some hard-to-find parsing errors (works in one version of Chrome and Firefox, but not in another). See documentation.Simply omit the parenthese, like this:
try {
// Code...
} catch {
// Code...
}
The specification gives the grammar for a catch block:
Catch :
catch (Identifier)Block
And goes on to state that:
When a catch clause catches an exception, its Identifier is bound to that exception
So it is a syntax error to omit the identifier from a catch block.
Agreed, it's mandatory so that you can handle the error fully - even if you know what the error is likely to be. In truth, just prod in a variable name and don't use it within your catch routine :)
MDN provides a solid content about the try-block:
When an exception is thrown in the
try-block,exception_var(i.e., theeincatch (e)) holds the exception value. You can use this identifier to get information about the exception that was thrown. This identifier is only available in thecatch-block's scope. If you don't need the exception value, it could be omitted.
function isValidJSON(text) {
try {
JSON.parse(text);
return true;
} catch {
return false;
}
}
catchbody block empty.(e)is optional. stackoverflow.com/a/56001361/6269864