time-to-botec/squiggle/node_modules/@stdlib/utils/async/try-catch/README.md

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# trycatchAsync

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

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## Usage

```javascript
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`.

```javascript
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`.

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## 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`).

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## Examples

<!-- eslint no-undef: "error" -->

```javascript
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();
```

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