FuncStack - Vanilla JS async tasks

Starts different tasks (functions), optionally asyncronous, and monitors the total progress

For any Browser and any NodeJS version.

Summary

The stack allows to execute a a bunch of tasks async, then wait for their completion to trigger another one. A task may use a resolve function, needed for AJAX requests and alike. onProgress will be triggered after each task with an overall status object and a the return result from a task. Module loading for AMD, CommonJS, Browser.

Author Nabil Redmann [email protected]

Licence MIT

Copyright use in your own code, but keep the copyright (except you modify it, then reference me)

Documentation

You should really generate the jsDoc based documentation: go to the path where this lib is, and use npm run doc or npm run devdoc (with overwritable internal methods). If you have trouble as windows user, use the included jsdoc_generate.cmd (but requires a reachable jsDoc installation, npm install -g jsdoc) .

Example

// init
var s = new FuncStack({
    debug:false,
    onProgress: function defaultHandlerExample(statusObj, curFn) {
        console.log('another one finished, still missing: ', statusObj.counts.left);

        if (curFn.x )
            console.log('Fn has an extra value (x):', curFn.x);
    }
})

// async execution
.add(function task1(){console.log('==1')})
// sync execution
.add(function task2(){console.log('==2 sync')}, FuncStack.ENUM_QUEUEMODE.DEFER)
// failing one
.add(function task3(){console.log('==3 err'); throw({msg: 'this is an error'});})
// transporting value to onProgress
.add(function task4(){console.log('==4'); this.x = 1;})
// ES6
.add( () => console.log('==5') )
// async execution + async callback
.add(function task6(data) {
    var done = data.preventDefault();
    console.log('==6 starting...');
    // simulate some async callback based function
    setTimeout(function() { 
        console.log('==6 finished');
        done('success');
    }, 2000);
})
// with a binded context
.add(function task7(){console.log('=='+this.val);}.bind({val: 7}))
// add an array of fns with optinally setting queue mode
.add([
    function task8()       {console.log('==8')},
    function task9()       {console.log('==9')},
    {fn: function task10() {console.log('task 10')}, addMode: 'defer'}
]}, FuncStack.ENUM_QUEUEMODE.DEFER)

// start consuming
.start();

ES6 awaitable

(async () => {
    
    // prepare tasks
    let fns = [
        () => console.log('task 1'),
        () => console.log('task 2'),
        {addMode: 'defer', fn: () => console.log('task 3') } // using addMode
    ];
    
    // await FuncStack completion
    let resultStatusObj = await FuncStack({}, fns).Promise();

    // check FuncStack status
    if (resultStatusObj.status == 'success')
        console.info('all fns done');
    else
        console.error(`some fn triggered an error (${ resultStatusObj.data.error.length }), but all rest completed (${ resultStatusObj.data.done.length })`);
})();

installation

This module can be included in a browser or in Node.js.

node installation.

npm i funcstackjs --save

Note

FuncStack's returned object has different methods:

build the docs to get them explained / index.js

.start()   // is also a resume after stop()
.stop()
.cancel() 
.add( task )
.push( task )
.length()
.restart()
.get( taskId ) // id or fn name
.clear()

a task function is declared like this:

function(data){ ... }

data gets infos about the current function/FuncStack state:

.fnCount
.queueMode
.funcStackReference
.fn
.preventDefault()  -> see 'resolve a ajax based task manually' below

You can return anything to let FuncStack handle your result as statusObj.result and move it to the done stack, or throw an error like throw new Error('could not compute'); to trigger .onError() and move it to the error stack.

details

signature param: [data]
    property keys: [fnCount, queueMode, funcStackReference, fn]
    property methods: [preventDefault()]
        preventDefault():                           (using this, return will be stopped and you must call resolveFn(status, result) to trigger task as proccessed -- use for ajax requests)
            returns: resolveFn()
                signature param: [status, result]   (status ['error', 'success', 'canceled'] in FuncStack.ENUM_STATUS.*)
                signature overloaded: [FuncStack.StatusNotificationObject]
                    signature param: [status, result] (same as resolveFn)
return: any                                         (triggers task as proccessed -> stack: done)
throw: error                                        (triggers task as proccessed -> stack: error)

onProgress statusObj has:

.status                  -> ['success', 'error', 'canceled']  -> FuncStack.ENUM_STATUS.*
.result                  -> anything returned from the fn
.queueMode               -> the queue mode used for this function
.data                    -> the _data object with the stacks containing the functions {queue, working, done, error}
.counts
    .start:     _data.startCount
    .left:      _data.working.length + _data.queue.length
    .finished:  _data.done.length    + _data.error.length
    .pending:   _data.queue.length
    .working:   _data.working.length
    .total:     _internal.fnCount

The FuncStack constructor:

var fncst = new FuncStack(options, initialFns);

Options can be a onCompleted callback or on object like:

options = {
    onCompleted: function defaultHandlerExample(statusObj) {console.log('!! FuncStack: executed all.');},
    onProgress:  function defaultHandlerExample(statusObj, curFn) {console.log('!! FuncStack: progress', arguments);},
    onStart:     function defaultHandlerExample(initialLen, dataObjRef, wasPaused) {},
    onError:     function defaultHandlerExample(statusObj, curFn) {},
    defaultQueueMode: FuncStack.ENUM_QUEUEMODE.ASYNC, // or .DEFER
    enforceDefaultQueueMode: false,
    manualConsume: false,                             // if you want to call _consume manually, to work the next block of functions (honouring async and defer) - e.g. for building an interator
    addMode: FuncStack.ENUM_ADDMODE.BOTTOM,           // add new fns to bottom or top / like a queue or stack
    debug:   false
}

initalFns (and .add()):

• a single function
• an array of functions
• an array of objects with functions: {addMode:bool, fn:function}

.get() returns an object of type FuncStack.FnInfoObject:

• fn -> the function / task
• stack -> the stack name where the task ended in
• pos -> the position within the stack
• id -> the internal identifier

about async and defer:

• async will start them in order as fast as possible without waiting for completion,
• defer will wait for previous defer task or all previous async tasks to start the new one

about returns from fns / results:

these will be passed to onProgress()

checking for tasks in the queues:

either use var x = theFuncStack.get(id or fn).stack; or mess with the internals theFuncStack._data.* array

adding values to transport to progress:

within the task, you can use this.value = 'something'; and in onProgress(statusObj, curFn) use if (curFn.value) ....

identifying a task in onProgress:

in onProgress(statusObj, curFn) you can:

• curFn.name == 'abc'
• this.get(curFn).id -> .stack and more

let the task check its own status for 'canceled' and paused:

within your async function, you may use myFuncStack.get(this).stack == FuncStack.ENUM_STATE.CANCELED to check, if it has been moved to the error stack - since it has not returned yet / called done(), there is no other reason

also: you could check myFuncStack.isStopped == true -> that tells, if tasks are currently consumed - but the current task should finish anyway. This will change if manualConsume was set to true.

resolve a ajax based task manually:

if you used var done = data.preventDefault() to handle the ending of your task by your self (going the async way), done will be a resolveFn(status, result) method call, which is actually an overloaded FuncStack.StatusNotificationObject. You have to call it, to trigger the task as proccessed and let FuncStack do its finishing job. Pass a status (['error', 'success', 'canceled'] in FuncStack.ENUM_STATUS.*) and any result you wish. 'error' will trigger .onError().

• first of, create your task with 1 param 'data' (function(data) {...}):

  • var done = data.preventDefault();

• then call in your ajax/async success:

  • done('success');

• .. which is the short version for (in expanded order, all being the same - undefined being no .result to be returned on the statusObj):

  done( 'success', undefined )
  done( FuncStack.ENUM_STATUS.SUCCESS, undefined )
  done( new FuncStack.StatusNotificationObject( FuncStack.ENUM_STATUS.SUCCESS, undefined ) )

• done() has 2 signatures:

  done( status, optionalResult )
  done( FuncStack.StatusNotificationObject(status, optionalResult) )

Change

• 1.0.4 Added support for [{addMode:bool, fn:function}, ..] as array type for add and initial fns, more readme infos.
• 1.0.3 Fixed readme about .count; actually being .counts, added more readme infos.
• 1.0.2 Fixed package info to make it requireable/importable by package name in NodeJS.