step-object

More Object based creation of 'step' functions

npm install step-object
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Object based creation of step functions.

Still an experiment at this stage.

Step Creation

var StepObject = require('step-object'),
    fs = require('fs');

var ReadDir = StepObject({

  _filter: function(files){
    var filteredFiles;

    //some filter logic
    return filteredFiles;
  },

  queue: function(path){
    fs.readdir(path, this);
  },

  read: function(err, files){
    if(err){
      throw err;
    }

    return this._filter(files);
  },

}, ['queue', 'read']);

ReadDir(function(err, files){
  //files is the result of read
});

Testing

One problem I ran into using step initially was gaining access to the scope in which the steps actually execute in.

I still perfer to specify the behaviour of each function which becomes very difficult if these functions utlize the shared contex to store information.

The below will give you a reference to the the context the step execution. This is the same object you refer to when using 'this' inside of your step methods.

//Note that this will not call queue from the above example
var subject = require('step-object/lib/mock-step-object')(ReadDir);

subject.queue //

Its important for me to note that this works via a simple hack where by not returning anything in a function the step execution halts because its effectivly waiting for a callback to execute.

So if you did the following:

subject(); 
//(which is the same as `this()` or next inside of step scope)

It will cause werid things to happen such as two steps executing without waiting for the other to finish.

Group / Parallel

The .group and .parallel functions are overriden to return themselves. This is so you can spy for them inside of your tests.

Methods / Order

You can also gain access to methods and order of the StepObject at anytime with:

ReadDir.methods //{queue: ....}
ReadDir.order //['queueRead', 'fsReadDir']

License

See LICENSE (MIT)

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