async-extensions

is an extension library for ts/js with async helpers using Promises control flow and async/await syntax!

These helper functions are attached to Array's prototype

The package includes typings.

The functions are:

• mapAsync<T, W>
• forEachAsync<T>
• filterAsync<T>

These helpers behave like similary named ones of the array's prototype and are waiting all promises to be resolved/rejected.

If defaultValueOrCatchHandler parameter is setted (for mapAsync and filterAsync) its value is returned for rejected promises or, if it is a function, its returning value is returned.

mapAsync<T, W>

generic types are:

• T: is list items' type
• W: is returned items' type

parameters:

• cback: map's callback
• defaultValueOrCatchHandler?: (optional) when an exception is raised from cback function then this parameter is executed and its returning value is returned if it is a function, otherwise its value is returned. If this parameter is not setted then this helper method behaves like Promise.all (which is called under the hood) as per rejecting the entire promise as soon as one item rejects.

note:

• this helpers was before Promise.allSettled (ES2020) era, of which has similar behaviour but the default value/factory

forEachAsync<T>

generic types are:

• T: is list items' type

parameters:

• cback: map's callback
• catchHandler?: as per previous helper this is a catch function for every item which reises an exception. It defaults to a NoOp function that ensures that all items are executed and waited for.

note:

• behaves similary to Promise.allSettled but not returning anything (other than a resolved promise with no resolved object)

filterAsync<T>

generic types are:

• T: is list items' type

parameters:

• cback: filter's callback
• defaultValueOrCatchHandler? (as per previous mapAsync<T, W> function)

note:

• mantains the items order (as per Promise.resolve)

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install with:

npm install async-extensions --save

TODO

• docmuentation
• examples
• tests