State-them NPM

state-them

Reactive UI framework for front-end JS. It has: 1. Template engine: For creating HTML nodes

let a =5;
let template = html`<div some=${a+1} .prop1=${"hello"} @click=${()=>console.log("do_something")}>${a}</div>`;
render(template,document.body);

StateMachine for creating state and StateMachineWidget to react to those states

class Counter extends StateMachine{
    constructor(){
        super({
            model:{
                "init":{
                    "increment":"init",
                    "decrement":"init"
                }
            }
        });
        this.count=0;
    }

    increment(){
        this.count++;
    }
    decrement(){
        this.count++;
    }
}

class CounterWidget extends StateMachineWidget{
    constructor(){
        super({
            machineName:"Counter1",
            hostedMachines:{
                Counter1:new Counter()
            }
        });
    }

    build(state){
        return html`<div>
        <div>
            <button @click=${e=>this.machine.do("increment")}>+</button><button @click=${e=>this.machine.do("decrement")}>-</button>
        </div>
        <div>
            ${this.machine.count}
        </div>
        </div>`;
    }
}
custom.defineElement("counter-wid",CounterWidget);

Via Model you can define possible states of machines and which action on a state will convert to which state on the machine. You can integrate this machine with even other machines. See main.html file for complete example of what all it can do.

Usage notes

A StateMachineWidget automatically searches the state machine it depends upon in the DOM tree. The State machine must be either hosted to itself using hostedMachines property of input config, else it searches it in its parent node , and its parent node until to document.
To change state of a StateMachine do method is called along with a action name and an optional data if required: do(actionName,data).
A StateMachine can be integrated with states from other machines,so that when there states changes the state on this machine can be changed. integrateWith property of config for StateMachine constructor is used to do this integration.
```
    integrateWith:{
        Incrementor1:{
            "changed":{
                "init":"changeIncrement"
            }
        }
    }
```
Here a StateMachine is integrated with another StateMachine with name Incrementor1. Whenever the state of Incrementor1 changes to changed, and the listener machine is in init state than itsdo("changeIncrement",Incrementor1StateMachineInstance) will be called.
Use repeat function to create efficiently updating a list of items.

let items=[10,20,30];
html`<ol>
${repeat(items,i=>i,(item,index,_id)=>{
    return html`<li>${item}</li>`;
})}
</ol>`

This will produce a HTML of kind

<ol>
    <li>10</li>
    <li>20</li>
    <li>30</li>
</ol>

The signature for repeat function is repeat(listOfItems,idFunction,templateFunction). listOfItems which needs to be repeated upon idFunction needs to create a unique id for each element. If Id of an element changes, than only it get re-rendered * templateFunction is used to create the template which needs to repeated for the list of items.

It will auto update only those items which gets updated, if idFunction is properly designed to cater to change id if data item changes.

Attribute can be modified using

html`<div customAtt=${some_varibable}></div>`

Add event listeners

html`<div @event=${some_handler}></div>`

Add properties

html`<div .prop=${some_value}></div>`

Error Codes

Different error codes are used , to make final built as small as possible.

1 : Integrated Machine with which this machine is integrated is not found in DOM tree.

{
    ec:1,//error code
    im:"m1",//machines with with its integrated,
    m:"name"// name of this machine
    he: "host-element"//element on which this machine is hosted
}

2: No such action found, while calling do method on a machine.

{
    ec:2,//error code
    am:"action_name",
    m:"name"// name of this machine
    he: "host-element"//element on which this machine is hosted
}

3: DEPRECATED : If an action do not exist the state will simply transform as per model. For action to take place, one must define a function on state machine with the action name. This error code indicates that no such method is found on the state machine.

{
    ec:3,
    an: "action_name",
    m:"name"// name of this machine
    he: "host-element"//element on which this machine is hosted
}

4: A StateMachineWidget depends upon a StateMachine, however it cannot find it upon connection in the DOM tree.

{
    ec:4,
    m:"name"// name of this machine
    he: "host-element"//element on which this machine is hosted
}

5: No build function found on the StateMachineWidget.

{ec: 5, w:"widget-name"}

Release Note

1.0.5

Bug fix: An item can have a slot only if it has a shadow. There was confusion in code for differentiating between custom elements with children and one without. So after this bug fix, a current node children will be skipped if its a custom element and has no shadow.

1.0.4

Default value of for StateMachineWidget constructor. Now no more required to define constructor, if there is no super call.
Added isShadow in StateMachineWidget constructor to set default shadow state
Bug fixed for slotted items: should use shadow when a component has slots.