@stdlib/utils-async-try-catch
v0.2.2
Published
If a function does not return an error, invoke a callback with the function result; otherwise, invoke a callback with a value `y`.
Downloads
25
Readme
trycatchAsync
If a function does not return an error, invoke a callback with the function result; otherwise, invoke a callback with a value
y
.
Installation
npm install @stdlib/utils-async-try-catch
Usage
var trycatchAsync = require( '@stdlib/utils-async-try-catch' );
trycatchAsync( x, y, done )
If a function x
does not return an error, invokes a done
callback with the function result; otherwise, invokes a done
callback with a value y
.
var randu = require( '@stdlib/random-base-randu' );
function x( clbk ) {
setTimeout( onTimeout, 0 );
function onTimeout() {
if ( randu() > 0.5 ) {
return clbk( null, 1.0 );
}
clbk( new Error( 'oops' ) );
}
}
function done( error, result ) {
if ( error ) {
console.log( error.message );
}
console.log( result );
}
trycatchAsync( x, -1.0, done );
The function x
is provided a single argument:
clbk
: callback to invoke upon function completion
The callback accepts two arguments:
error
: error objectresult
: function result
The done
callback is invoked upon function completion and is provided two arguments:
error
: error objectresult
: either the result ofx
or the provided valuey
If the function x
does not return a truthy error
argument, the error
argument provided to the done
callback is null
. If x
does return a truthy error
argument, the done
callback is invoked with both the error
and the provided value y
.
Notes
- Execution is not guaranteed to be asynchronous. To guarantee asynchrony, wrap the
done
callback in a function which either executes at the end of the current stack (e.g.,nextTick
) or during a subsequent turn of the event loop (e.g.,setImmediate
,setTimeout
).
Examples
var randu = require( '@stdlib/random-base-randu' );
var trycatchAsync = require( '@stdlib/utils-async-try-catch' );
var i;
function next() {
trycatchAsync( x, 'beep', done );
}
function x( clbk ) {
setTimeout( onTimeout, 0 );
function onTimeout() {
if ( randu() > 0.9 ) {
return clbk( null, 'BOOP' );
}
clbk( new Error( 'oops' ) );
}
}
function done( error, result ) {
if ( error ) {
console.log( error.message );
}
i += 1;
console.log( result );
if ( i < 100 ) {
return next();
}
}
i = 0;
next();
See Also
@stdlib/utils-try-catch
: if a function does not throw, return the function return value; otherwise, returny
.@stdlib/utils-async/try-then
: if a function does not return an error, invoke a callback with the function result; otherwise, invoke a second function.
Notice
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.