chainjs

chainjs

An asynchronous callback's flow controller, chaining async function callbacks. simple and clear than using promise. I use it in node.js server and webapp.

Install

npm install chainjs

Usage

use in node:

var Chain = require('chainjs')

Chain(function (chain) {
        console.log('initialize');
        chain.next('none');
    })
    .some(function (chain) {
        chain.wait(300, 'then go to next')
    }, function (chain) {
        chain.wait(200, 'then go to next')
    }, function (chain) {
        chain.wait(100, 'then go to next')
    })
    .then(function (chain, data) {
        console.log(data); // --> then go to next
        chain.next('say hello');
    })
    .final(function (chain, data) {
        console.log(data); // --> say hello
    });

API

Each step's handler has been passed the chain instance as the first argument

Chain(func, func1, ..., funcN)

Instancing a chain and define a chain step

Chain(func /*, func1, ..., funcN*/);

.then(func, func1, ..., funcN)

Define chain steps, if a then step has multiple functions, step over after each func call chain.next()

Chain(func).then(func1).then(funcA1, funcA2, funcA3)

.retry()

Call current step handler once again (recursive).

var flag
Chain(function (chain, data) {
    if (flag) {
        return chain.next()
    }
    flag = true
    chain.retry()
}).start('value')

.some(func, func1, ..., funcN)

When call chain.next in which handler of "some" step will be over current step.

Chain(func).then(func1).some(funcA1, funcA2, funcA3)

.each(func, func1, ..., funcN)

Call each handlers in sequence.

Chain(func).then(func1).each(funcA1, funcA2, funcA3)

.start(data)

Start running the chain, and could pass data to initial step.

Chain(func).then(func1).then(func2).start();

.destroy()

Destroy the chain, mark the chain as ending and destroy local variable, but not call ending funtions

notice: after use chain.destroy(), the chain contiue execute current step handler, so use with return for stoping current step excution

Chain(func).then(function (chain) {
    chain.destroy();
    return;
}).start();

.next(nextParams)

Go to next step

chain.next();
// pass params to next step handler
chain.next(data);

.wait(time, nextParams)

Waiting some time then call next step

// pass params to next step handler
chain.wait(5000, data); // wait 5s then call next

.end(finalParams)

End up chain steps, mark the chain as ending, for cross steps data sharing

chain.end();
// pass params to final handler
chain.end(data);

.final(finalHandler)

Pushing final handler which will be invoke when chain.end() or chain step is ending

.data(savingData)

Saving data in current chain

// set data
chain.data('param', param);
// get data
chain.data('param');
// get all data
var chainData = chain.data();

Testing

Chainjs using mocha for BDD test, run below cli to run testing in nodejs

npm test

Example

var Chain = require('chainjs');
var someStepCount = 0;
var parallelCount = 0;

Chain(function (chain) {
        // save param
        chain.data('chain:param', 'Chain initial step data');
        chain.next({message: 'Next step'});
    })
    .some(function (chain, param) {
        someStepCount ++;
        chain.wait(2000, 'step is "some-1"');
    }, function (chain, param) {
        someStepCount ++;
        chain.wait(1000, 'step is "some-2"');
    })
    .then(function (chain, msg) {
        console.log(msg); // step is "some-2
        // Step over when last step has one hander called
        console.log(someStepCount); // 1
        chain.next();
    })
    .then(function (chain) {
        parallelCount ++;
        chain.next();
    }, function (chain) {
        parallelCount ++;
        chain.next();
    }, function (chain) {
        parallelCount ++;
        chain.next();
    })
    .then(function (chain) {
        // all handlers had been called in last step
        console.log(parallelCount); // 3
        chain.end();
    })
    .then(function (chain) {
        //prev step had call chain.end(), so this step will be skiped
    })
    .final(function (chain) {
        var param = chain.data('chain:param');
        console.log(param); // "Chain initial step data"
    })
    .context(this)
    .start(); // starting chain execute

Change Log

See change logs

License

The MIT License (MIT)

Copyright (c) 2013 guankaishe

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Changelog

Version 0.1.4 - 2015/1/4

• [Feature] add each() api for call each step's handlers in sequeue