Wrap Promise

Wrap a promise within before and after callbacks.

Installation

$ npm install @aercolino/wrap-promise

This is not related to wrap-promise.

Usage

const { $wrapPromise } = require('@aercolino/wrap-promise');

const regular = $wrapPromise($promise, before, after);

const special = $wrapPromise($promise, before, afterFulfillment, afterRejection);

• $promise and before are called with no arguments.

• In the regular case:

  • after is called with the fulfillment { value } or the rejection { reason }.

  • no matter whether executing the fulfillment line or the rejection line, after is called in both cases, without changing line, without changing the fulfillment value nor the rejection reason. (i.e. after return value is discarded)

• In the special case:

  • afterFulfillment is called with the fulfillment { value }.

  • afterRejection is called with the rejection { reason }.

  • afterFulfillment is called only if executing the fulfillment line, without changing line, without changing the fulfillment value.

  • afterRejection is called only if executing the rejection line, by default changing to the fulfillment line (i.e. swallowing the rejection) and making afterRejection return value the new fullfilment value.

    If you prefer to stay on the rejection line, just throw from inside afterRejection, as usual.

Example

// test.js
require('console.mute');
const { $wrapPromise } = require('@aercolino/wrap-promise');

function muted($fn, ...args) {
    return $wrapPromise(
        () => $fn(...args),
        () => {
            console.mute();
        },
        () => {
            console.resume();
        },
    );
}

...
it('should be quiet when calling this'
    ...
it('should quietly run that noisy function too', function() {
    return muted(noisy, 'bye bye', 'clutter')
        .then(() => {
            expect(that).to.have.been.called;
        });
});
it('should be quiet when calling that'
    ...
...

// console
$ npm test

    ...
    ✓ should be quiet when calling this
    ✓ should quietly run that noisy function too
    ✓ should be quiet when calling that
    ...

5 passing (64ms)

Tests

$ npm test