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Romain Lebesle
Romain Lebesle

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userinterface.js - Small front-end library

#javascript #webdev

userinterface.js is a front-end library built around the idea that logic relating to how the visual looks and how the visual works should be distinguished.

Getting started

Installing

Scaffold

See https://github.com/thoughtsunificator/userinterface.js-skeleton.

Standalone

git submodule add https://github.com/thoughtsunificator/userinterface.js.git lib/userinterface.js

Add userinterface.js to the head section of your web page:

<script src="./lib/userinterface.js/src/userinterface.js"></script>
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Model

A Model is an object representation of a Node.
It has three required properties depending on the method: name, method and properties or callback,

The name property will be the identifier of your model it will be used whenever you need to run your model but also to associate a binding to your model.
The method property will describe how your model should be ran.
The properties and callback properties will contain the properties of your Elements.

A Model often goes along with a Binding and an Object.

Basic model

Here we create a model named simplemodel using the method appendChild it has a one LI element child. LI has the className simplemodel and textContent Myfirst simple model.
This model uses the textContent, className and tagName propertie however you might use any Element properties the DOM API offers.

src/userinterface/simplemodel.js

UserInterface.model({
  name: "simplemodel",
  method: UserInterface.appendChild,
  properties: {
    tagName: "li", // required
    className: "simplemodel",
    textContent: "My first simple model"
  }
});
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UserInterface.runModel("simplemodel", { parentNode: document.querySelector("ul") });
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Output:

<ul>
  <li class="simplemodel">My first simple model</li>
</ul>
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Children

In the previous example we created a simple model, but what if we wanted to do more and add some children to it ?
The children property is here for that, it is an Array where you can specify child elements.

src/userinterface/children.js

UserInterface.model({
  name: "children",
  method: UserInterface.appendChild,
  properties: {
    tagName: "div",
    className: "model",
    children: [
      {
        tagName: "div",
        className: "child",
        textContent: "My first child"
        // and so on..
      }
    ]
  }
});
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UserInterface.runModel("children", { parentNode: document.body });
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Output:

<body>
  <div class="model">
    <div class="child">My first child</div>
  </div>
</body>
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Callback

Models are required to have either the properties property or callback property, but exactly what does the callback property do ?
It is used when you want to echo some data in your model.

For example here, we have a model called echomodel that has the callback property. This property works the same as the properties property does except that an extra step is added before your model is ran.
The callback will return a properties object accordingly to the data you passed through runModel.

src/userinterface/echomodel.js

UserInterface.model(
  name: "echomodel",
  method: UserInterface.appendChild,
  callback: data => ({
    tagName: "p",
    className: "echomodel",
    textContent: "My "+data.text+" model"
  })
);
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UserInterface.runModel("echomodel", { parentNode: document.body, data: {"text": "echo" } });
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Output:

<p class="echomodel">My echo model</p>
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Processed properties

  • children Add children to an element

Binding

A Binding is a callback function that, when bound to a model, is automatically called whenever the model has ran.
Bindings will make your models more alive, an example of that would be adding an event listener to your model, that is the place where you will be doing it.

You can also do much more such as using event listeners to connect all of your models together!

A Binding is way to give life to your models enabling them to do things whenever their respective method is executed.
That means if you want to add a listener to an Element that's where you will be doing it.

In this example we will change the textContent of our model root element.

src/userinterface/button.js

UserInterface.model({
  name: "button",
  method: UserInterface.appendChild,
  properties: {
    tagName: "button"
  }
});

UserInterface.bind("button", function(element) {
  element.textContent = "bound";
});
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UserInterface.runModel("button", { parentNode: document.body });
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Output:

<button>bound</button>
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Methods

  • appendChild Append your model to the target

  • insertBefore Insert your model before the target

  • removeElement Remove the target

  • replaceElement Replace the target with your model

  • updateElement Update the target according to your model

  • wrapElement Wrap the target inside your model

  • removeListeners Remove the listeners of the target

Objects

Objects are the backbone of your models they will store and manipulate data for your Binding.
That's where you want to hide the complicated stuff.

Listeners

Listeners enable intercommunication for your models.

Main object

You usually wants to have a main object that you will pass to most of your models so that they communicate with each other through a central.

Note that you are not forced to have one and you could have multiple observables and still be able to handle inter-model communication.

Most of the time we call it application.

Listening to events

In this example we are creating and running a model called myModel that will listen for the event greeting on through the application context.

A Context represent a reserved area (a channel) that events will be bound to, they're often represented as an instance of an object but could pretty much be anything.

src/userinterface/my-model.js

UserInterface.model({
  name: "myModel",
  method: UserInterface.appendChild,
  properties: {
    tagName: "div"
  }
});
UserInterface.bind("myModel", function(element, application) {

  UserInterface.listen(application, "greeting", async (message) => {
    console.log(message)
  })

});
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const application = {}

UserInterface.runModel("myModel", { parentNode: document.body, bindingArgs: [application] });
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For the moment we are only listening to the greeting event, we haven't announced anything to it yet.

Announcing events

In the previous example we setup a greeting listener on application.

Now, let's try to announce to the event.

src/userinterface/another-model.js

UserInterface.model({
  name: "anotherModel",
  method: UserInterface.appendChild,
  properties: {
    tagName: "div"
  }
});
UserInterface.bind("anotherModel", function(element, application) {

  UserInterface.announce(application, "greeting", "Hello!");

});
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const application = {}

UserInterface.runModel("myModel", { parentNode: document.body, bindingArgs: [application] });
UserInterface.runModel("anotherModel", { parentNode: document.body, bindingArgs: [application] });
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If everything went well you should be able see a Hello! log message in the console.

Removing event listeners

Sometimes you might want your model to be dynamically added and removed, meaning that it will be added upon an action and removed upon another action.

Usually what you want to do is to create _listener variable and push all the listeners to this array and then remove them as needed using forEach for example.

In this example, we create a listener message and remove it whenever the event done is emitted.

UserInterface.bind("myDynamicModel", function(element, application) {

  const _listeners = []

  _listeners.push(UserInterface.listen(application, "message", async data => {
    console.log(data)
  }))

  _listeners(UserInterface.listen(application, "done", async () => {
    _listeners.forEach(listener => UserInterface.removeListener(listener))
  }))

})
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API

You can read the API by visiting https://thoughtsunificator.github.io/userinterface.js.

Common errors

Cannot set property 'binding' of undefined

UserInterface.js could not find the model specified when calling UserInterface.bind.

Cannot destructure property 'method' of 'model' as it is undefined.

UserInterface.js could not find the model specified when calling UserInterface.runModel.

Feel free to open an issue if you need assistance.

Collection

userinterface.js also provides a collection that contains a few basic models to get you started. See https://github.com/thoughtsunificator/userinterface.js-collection.

Extensions

See https://github.com/topics/userinterface-js-extension.

Demos

See https://github.com/topics/userinterface-js-demo.

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