Migration.guide.md

Migration Guides

Migration from v.4.x.x to v.5.x.x.

FSM Description

• FSM description property 'table' was renamed to behavior;
• Data fields for stateData should be in fsm machine definition. Missing keys will be ignored;

Transition functions

• Transition functions have different set and arrangment of arguments;

 // ver. 4 ->
    function transitionFunction ( task, dependencies, stateData, data ) {
        // ...code here
        return task.done(transitionResult);
    }
// ver. 5 ->
    // stateData is not directly available. Use the function extractList to get the data you need;
    // look at the example below:
    function transitionFunction ( {task, state, dependencies, extractList }, data ) {
        // ...code here
        const [ top, something, else ] = extractList ([ 'a', 'b', 'c' ]);
        // get 'a' from stateData and write in variable 'top';
        // get 'b' from stateData and write in variable 'something';
        // get 'c' from stateData and write in variable 'else';
        const transitionResult = { 
                                      success : true
                                    , stateData : { 
                                                        // ...setup stateData changes here
                                                } 
                                    , result : 
                            };
        task.done(transitionResult);
    }

• Transition functions can update only defined stateData fields. Not defined data-segments or properties will be ignored;

 const machine = {
                    behavior : [
                                    // transition condition rows here..
                            ]
                    stateData : {
                                    a : 1 // <- this is the only allowed field in stateData;
                                }
            }

 const lib = {
            trans ({task}) { // transition function
                    stateData = { a : 2, b : 3, c : 4 }; // <- only 'a' is defined in machine.stateData;
                    task.done({ success : true, stateData }) // 'b' and 'c' will be ignored;
                }
        }

• If you don't know what is defined in stateData, just request a extractList without any arguments;

function trans ({task, extractList}) {
    const stateDataCopy = extractList(); // <- will return state fields from stateData wrapped in object    
}

• Fill stateData with primitive values and objects that are JSON compatible!

Migration from v.1 to v.2

Project was started with simplest posible implementation. I like the approach and want to extend it. Reasons:

• Some of my transition function contain asynchronous events;
• Describe chain of actions inside the transition condition records;
• Chain of action on positive and negative transition end;

So... about changes:

Transition complete

• Version 1: Transition function should return transitionResult object.
• Version 2: Transition function receives as first param task. Task is askForPromise object. Transition is complete on task.done(transitionResult).
• Changes: Find return statement and convert it to task.done:

    // ver. 1 ->
    ...
    return { success : true }
    // ver. 2 ->
    ...
    task.done ({ success : true })