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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

trycatchAsync

NPM version Build Status Coverage Status

If a function does not return an error, invoke a callback with the function result; otherwise, invoke a callback with a value y.

Usage

To use in Observable,

trycatchAsync = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-async-try-catch@umd/browser.js' )

To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:

var trycatchAsync = require( 'path/to/vendor/umd/utils-async-try-catch/index.js' )

To include the bundle in a webpage,

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/utils-async-try-catch@umd/browser.js"></script>

If no recognized module system is present, access bundle contents via the global scope:

<script type="text/javascript">
(function () {
    window.trycatchAsync;
})();
</script>

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 object
  • result: function result

The done callback is invoked upon function completion and is provided two arguments:

  • error: error object
  • result: either the result of x or the provided value y

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

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/utils-async-try-catch@umd/browser.js"></script>
<script type="text/javascript">
(function () {

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();

})();
</script>
</body>
</html>

See Also

  • @stdlib/utils-try-catch: if a function does not throw, return the function return value; otherwise, return y.
  • @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

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.