promise-chain-break

PromiseBreak

Description

Pb is little, but powerfull utility module made to close some gaps in JavaScript Promises. Please feel free to provide any requests to new functionality. It is based on https://github.com/petkaantonov/bluebird/issues/581 issue.

Usage

Installation

    $ npm install --save promise-chain-break

    const pb = require('promise-chain-break');

Wrapping

To make magic work you need to wrap over Promise callbacks with pb at least at one level lower then you planing to pass flow control commands and to the end of chain. But it is better for code maintance to wrap all callbacks at once.

    db.getData()
    .then(pb((data) => {
    }))
    .then(pb(() => {
    }))
    .then(pb(() => {
    }))
    .catch((error) => {
        console.error(error);
    });

Break Promise

If you need to break a chain of promises

    db.getData()
    .then(pb((data) => {
        if (!data.someCheck()) {
            tellSomeone();
 
            // All other '.then' calls will be skiped
            return pb.BREAK;
        }
    }))
    .then(pb(() => {
    }))
    .then(pb(() => {
    }))
    .catch((error) => {
        console.error(error);
    });

Skip Next Promise

If you decided to use one call in chain only in some cases.

    db.getData()
    .then(pb((data) => {
        if (!data.needSomeMoreDBWork) {
            // Next '.then' call will be skiped
            return pb.SKIP_NEXT;
        }
    }))
    .then(pb(() => {
        return db.doMoreStuff();
    }))
    .then(pb(() => {
    }))
    .catch((error) => {
        console.error(error);
    });