Modules

Component ⇐ Rasti.View

Components are a special kind of View that is designed to be easily composable, making it simple to add child views and build complex user interfaces.
Unlike views, which are render-agnostic, components have a specific set of rendering guidelines that allow for a more declarative development style.
Components are defined with the Component.create static method, which takes a tagged template string or a function that returns another component.

Extends: Rasti.View
See: Component.create

Param Type Description
options object Object containing options. The following keys will be merged to this: model, state, key, onDestroy, onRender, onCreate, onChange.

Properties

Name Type Description
key string A unique key to identify the component. Used to recycle child components.
model object A Rasti.Model or any emitter object containing data and business logic. The component will listen to change events and call onChange lifecycle method.
state object A Rasti.Model or any emitter object containing data and business logic, to be used as internal state. The component will listen to change events and call onChange lifecycle method.

Example

import { Component, Model } from 'rasti';
// Create Timer component.
const Timer = Component.create`
    <div>
        Seconds: <span>${({ model }) => model.seconds}</span>
    </div>
`;
// Create model to store seconds.
const model = new Model({ seconds: 0 });
// Mount timer on body.
Timer.mount({ model }, document.body);
// Increment `model.seconds` every second.
setInterval(() => model.seconds++, 1000);

component.subscribe(model) ⇒ Rasti.Component

Listen to change event on a model or emitter object and call onChange lifecycle method. The listener will be removed when the component is destroyed. By default the component will be subscribed to this.model and this.state.

Kind: instance method of Component
Returns: Rasti.Component - The component instance.

Param Type Description
model Rasti.Model A model or emitter object to listen to changes.

component.onCreate(options)

Lifecycle method. Called when the view is created, at the end of the constructor.

Kind: instance method of Component

Param Type Description
options object The view options.

component.onChange(model, changed)

Lifecycle method. Called when model emits change event. By default calls render method. This method can be extended with custom logic. Maybe comparing new attributes with previous ones and calling render when needed.

Kind: instance method of Component

Param Type Description
model Rasti.Model The model that emitted the event.
changed object Object containing keys and values that has changed.
[…args] any Any extra arguments passed to set method.

component.onRender(type)

Lifecycle method. Called when the view is rendered.

Kind: instance method of Component

Param Type Description
type string The render type. Can be render, hydrate or recycle.

component.onDestroy(options)

Lifecycle method. Called when the view is destroyed.

Kind: instance method of Component

Param Type Description
options object Options object or any arguments passed to destroy method.

component.partial(strings, …expressions) ⇒ Array

Tagged template helper method. Used to create a partial template.
It will return a one-dimensional array with strings and expressions.
Components will be added as children by the parent component. Template strings literals will be marked as safe HTML to be rendered. This method is bound to the component instance by default.

Kind: instance method of Component
Returns: Array - Array containing strings and expressions.

Param Type Description
strings TemplateStringsArray Template strings.
…expressions any Template expressions.

Example

import { Component } from 'rasti';
// Create a Title component.
const Title = Component.create`
    <h1>${self => self.renderChildren()}</h1>
`;
// Create Main component.
const Main = Component.create`
    <main>
        ${self => self.renderHeader()}
    </main>
`.extend({
    // Render header method.
    // Use `partial` to render an HTML template adding children components.
    renderHeader() {
        return this.partial`
            <header>
                <${Title}>${({ model }) => model.title}</${Title}>
            </header>
        `;
    }
});

Component.markAsSafeHTML(value) ⇒ Rasti.SafeHTML

Mark a string as safe HTML to be rendered.
Normally you don't need to use this method, as Rasti will automatically mark string literals as safe HTML when the component is created and when using the Component.partial method.
Be sure that the string is safe to be rendered, as it will be inserted into the DOM without any sanitization.

Kind: static method of Component
Returns: Rasti.SafeHTML - A safe HTML object.

Param Type
value string

Component.extend(object)

Helper method used to extend a Component, creating a subclass.

Kind: static method of Component

Param Type Description
object object Object containing methods to be added to the new Component subclass. Also can be a function that receives the parent prototype and returns an object.

Component.mount(options, el, hydrate) ⇒ Rasti.Component

Mount the component into the dom. It instantiate the Component view using options, appends its element into the DOM (if el is provided). And returns the view instance.

Kind: static method of Component

Param Type Description
options object The view options.
el node Dom element to append the view element.
hydrate boolean If true, the view will hydrate existing DOM.

Component.create(strings, …expressions) ⇒ Rasti.Component

Takes a tagged template string or a function that returns another component, and returns a new Component class.

  • The template outer tag and attributes will be used to create the view's root element.
  • The template inner HTML will be used as the view's template.
  const Button = Component.create`<button class="button">Click me</button>`;
  • Template interpolations that are functions will be evaluated during the render process, receiving the view instance as an argument and being bound to it. If the function returns null, undefined, false, or an empty string, the interpolation won't render any content.
  const Button = Component.create`
      <button class="${({ options }) => options.className}">
          ${({ options }) => options.renderChildren()}
      </button>
  `;
  • Event handlers should be passed, at the root element as camelized attributes, in the format onEventName=${{'selector' : listener }}. They will be transformed to an event object and delegated to the root element. See View.delegateEvents.
  • Boolean attributes should be passed in the format attribute="${() => true}". false attributes won't be rendered. true attributes will be rendered without a value.
  const Input = Component.create`
      <input type="text" disabled=${({ options }) => options.disabled} />
  `;
  • If the interpolated function returns a component instance, it will be added as a child component.
  • If the interpolated function returns an array, each item will be evaluated as above.
  // Create a button component.
  const Button = Component.create`
      <button class="button">
          ${({ options }) => options.renderChildren()}
      </button>
  `;
  // Create a navigation component. Add buttons as children. Iterate over items.
  const Navigation = Component.create`
      <nav>
          ${({ options }) => options.items.map(
              item => Button.mount({ renderChildren: () => item.label })
          )}
      </nav>
  `;
  // Create a header component. Add navigation as a child.
  const Header = Component.create`
      <header>
          ${({ options }) => Navigation.mount({ items : options.items})}
      </header>
  `;
  • Child components can be added using a component tag.
  // Create a button component.
  const Button = Component.create`
      <button class="button">
           ${({ options }) => options.renderChildren()}
      </button>
  `;
  // Create a navigation component. Add buttons as children. Iterate over items.
  const Navigation = Component.create`
      <nav>
          ${({ options, partial }) => options.items.map(
              item => partial`<${Button}>${item.label}</${Button}>`
          )}
      </nav>
  `;
  // Create a header component. Add navigation as a child.
  const Header = Component.create`
      <header>
          <${Navigation} items="${({ options }) => options.items}" />
      </header>
  `;
  • If the tagged template contains only one expression that mounts a component, or the tags are references to a component, the component will be considered a container. It will render a single component as a child. this.el will be a reference to that child component's element.
  // Create a button component.
  const Button = Component.create`
      <button class="${({ options }) => options.className}">
          ${self => self.renderChildren()}
      </button>
  `;
  // Create a container that renders a Button component.
  const ButtonOk = Component.create`
      <${Button} className="ok">Ok</${Button}>
  `;
  // Create a container that renders a Button component, using a function.
  const ButtonCancel = Component.create(() => Button.mount({
      className: 'cancel',
      renderChildren: () => 'Cancel'
  }));

Kind: static method of Component
Returns: Rasti.Component - The newly created component class.

Param Type Description
strings string | function HTML template for the component or a function that mounts a sub component.
…expressions * The expressions to be interpolated within the template.

Emitter

Emitter is a class that provides an easy way to implement the observer pattern in your applications.
It can be extended to create new classes that have the ability to emit and bind custom named events.
Emitter is used by Model and View classes, which inherit from it to implement event-driven functionality.

Example

import { Emitter } from 'rasti';
// Custom cart
class ShoppingCart extends Emitter {
    constructor() {
        super();
        this.items = [];
    }

    addItem(item) {
        this.items.push(item);
        // Emit a custom event called `itemAdded`.
        // Pass the added item as an argument to the event listener.
        this.emit('itemAdded', item);
    }
}
// Create an instance of ShoppingCart and Logger
const cart = new ShoppingCart();
// Listen to the `itemAdded` event and log the added item using the logger.
cart.on('itemAdded', (item) => {
    console.log(`Item added to cart: ${item.name} - Price: $${item.price}`);
});
// Simulate adding items to the cart
const item1 = { name : 'Smartphone', price : 1000 };
const item2 = { name : 'Headphones', price : 150 };

cart.addItem(item1); // Output: "Item added to cart: Smartphone - Price: $1000"
cart.addItem(item2); // Output: "Item added to cart: Headphones - Price: $150"

emitter.on(type, listener)

Adds event listener.

Kind: instance method of Emitter

Param Type Description
type string Type of the event (e.g. change).
listener function Callback function to be called when the event is emitted.

Example

// Re render when model changes.
this.model.on('change', this.render.bind(this));

emitter.once(type, listener)

Adds event listener that executes once.

Kind: instance method of Emitter

Param Type Description
type string Type of the event (e.g. change).
listener function Callback function to be called when the event is emitted.

Example

// Log a message once when model changes.
this.model.once('change', () => console.log('This will happen once'));

emitter.off([type], [listener])

Removes event listeners.

Kind: instance method of Emitter

Param Type Description
[type] string Type of the event (e.g. change). If is not provided, it removes all listeners.
[listener] function Callback function to be called when the event is emitted. If listener is not provided, it removes all listeners for specified type.

Example

// Stop listening to changes.
this.model.off('change');

emitter.emit(type)

Emits event of specified type. Listeners will receive specified arguments.

Kind: instance method of Emitter

Param Type Description
type string Type of the event (e.g. change).
[…args] any Arguments to be passed to listener.

Example

// Emit validation error event.
this.emit('invalid');

Model ⇐ Rasti.Emitter

  • Orchestrates data and business logic.
  • Emits events when data changes.

A Model manages an internal table of data attributes and triggers change events when any of its data is modified.
Models may handle syncing data with a persistence layer. To design your models, create atomic, reusable objects that contain all the necessary functions for manipulating their specific data.
Models should be easily passed throughout your app and used anywhere the corresponding data is needed.
Rasti models store their attributes in this.attributes, which is extended from this.defaults and the constructor attributes parameter. For every attribute, a getter is generated to retrieve the model property from this.attributes, and a setter is created to set the model property in this.attributes and emit change and change:attribute events.

Extends: Rasti.Emitter

Param Type Description
attributes object Object containing model attributes to extend this.attributes. Getters and setters are generated for this.attributes, in order to emit change events.

Properties

Name Type Description
defaults object | function Object containing default attributes for the model. It will extend this.attributes. If a function is passed, it will be called to get the defaults. It will be bound to the model instance.
previous object Object containing previous attributes when a change occurs.

Example

import { Model } from 'rasti';
// Product model
class ProductModel extends Model {
    preinitialize() {
        // The Product model has `name` and `price` default attributes.
        // `defaults` will extend `this.attributes`.
        // Getters and setters are generated for `this.attributes`,
        // in order to emit `change` events.
        this.defaults = {
            name: '',
            price: 0
        };
    }

    setDiscount(discountPercentage) {
        // Apply a discount to the price property.
        // This will call a setter that will update `price` in `this.attributes`,
        // and emit `change` and `change:price` events.
        const discount = this.price * (discountPercentage / 100);
        this.price -= discount;
    }
}
// Create a product instance with a name and price.
const product = new ProductModel({ name: 'Smartphone', price: 1000 });
// Listen to the `change:price` event.
product.on('change:price', () => console.log('New Price:', product.price));
// Apply a 10% discount to the product.
product.setDiscount(10); // Output: "New Price: 900"

model.preinitialize(attributes)

If you define a preinitialize method, it will be invoked when the Model is first created, before any instantiation logic is run for the Model.

Kind: instance method of Model

Param Type Description
attributes object Object containing model attributes to extend this.attributes.

model.defineAttribute(key)

Generate getter/setter for the given key. In order to emit change events. This method is called internally by the constructor for this.attributes.

Kind: instance method of Model

Param Type Description
key string Attribute key.

model.get(key) ⇒ any

Get an attribute from this.attributes. This method is called internally by generated getters.

Kind: instance method of Model
Returns: any - The attribute value.

Param Type Description
key string Attribute key.

model.set(key, [value]) ⇒ this

Set an attribute into this.attributes.
Emit change and change:attribute if a value changes.
Could be called in two forms, this.set('key', value) and this.set({ key : value }).
This method is called internally by generated setters.
The change event listener will receive the model instance, an object containing the changed attributes, and the rest of the arguments passed to set method.
The change:attribute event listener will receive the model instance, the new attribute value, and the rest of the arguments passed to set method.

Kind: instance method of Model
Returns: this - This model.
Emits: event:change, change:attribute

Param Type Description
key string Attribute key or object containing keys/values.
[value] Attribute value.

model.toJSON() ⇒ object

Return object representation of the model to be used for JSON serialization. By default returns a copy of this.attributes.

Kind: instance method of Model
Returns: object - Object representation of the model to be used for JSON serialization.

View ⇐ Emitter

  • Listens for changes and renders the UI.
  • Handles user input and interactivity.
  • Sends captured input to the model.

A View is an atomic unit of the user interface that can render data from a specific model or multiple models. However, views can also be independent and have no associated data.
Models must be unaware of views. Views, on the other hand, may render model data and listen to the change events emitted by the models to re-render themselves based on changes.
Each View has a root element, this.el, which is used for event delegation.
All element lookups are scoped to this element, and any rendering or DOM manipulations should be done inside it. If this.el is not present, an element will be created using this.tag (defaulting to div) and this.attributes.

Extends: Emitter

Param Type Description
options object Object containing options. The following keys will be merged into the view instance: el, tag, attributes, events, model, template, onDestroy.

Properties

Name Type Description
el node | function Every view has a root DOM element stored at this.el. If not present, it will be created. If this.el is a function, it will be called to get the element at this.ensureElement, bound to the view instance. See View.ensureElement.
tag string | function If this.el is not present, an element will be created using this.tag and this.attributes. Default is div. If it is a function, it will be called to get the tag, bound to the view instance. See View.ensureElement.
attributes object | function If this.el is not present, an element will be created using this.tag and this.attributes. If it is a function, it will be called to get the attributes object, bound to the view instance. See View.ensureElement.
events object | function Object in the format {'event selector' : 'listener'}. It will be used to bind delegated event listeners to the root element. If it is a function, it will be called to get the events object, bound to the view instance. See View.delegateEvents.
model object A model or any object containing data and business logic.
template function A function that returns a string with the view's inner HTML. See View.render.

Example

import { View } from 'rasti';

class Timer extends View {
    constructor(options) {
        super(options);
        // Create model to store internal state. Set `seconds` attribute to 0.
        this.model = new Model({ seconds : 0 });
        // Listen to changes in model `seconds` attribute and re-render.
        this.model.on('change:seconds', this.render.bind(this));
        // Increment model `seconds` attribute every 1000 milliseconds.
        this.interval = setInterval(() => this.model.seconds++, 1000);
    }

    template(model) {
        return `Seconds: <span>${model.seconds}</span>`;
    }
}
// Render view and append view's element into the body.
document.body.appendChild(new Timer().render().el);

view.preinitialize(attrs)

If you define a preinitialize method, it will be invoked when the view is first created, before any instantiation logic is run.

Kind: instance method of View

Param Type Description
attrs object Object containing model attributes to extend this.attributes.

view.$(selector) ⇒ node

Returns the first element that matches the selector, scoped to DOM elements within the current view's root element (this.el).

Kind: instance method of View
Returns: node - Element matching selector within the view's root element (this.el).

Param Type Description
selector string CSS selector.

view.$$(selector) ⇒ Array.<node>

Returns a list of elements that match the selector, scoped to DOM elements within the current view's root element (this.el).

Kind: instance method of View
Returns: Array.<node> - List of elements matching selector within the view's root element (this.el).

Param Type Description
selector string CSS selector.

view.destroy(options) ⇒ Rasti.View

Destroy the view. Destroy children views if any, undelegate events, stop listening to events, call onDestroy lifecycle method.

Kind: instance method of View
Returns: Rasti.View - Return this for chaining.

Param Type Description
options object Options object or any arguments passed to destroy method will be passed to onDestroy method.

view.onDestroy(options)

onDestroy lifecycle method is called after the view is destroyed. Override with your code. Useful to stop listening to model's events.

Kind: instance method of View

Param Type Description
options object Options object or any arguments passed to destroy method.

view.addChild(child) ⇒ Rasti.View

Add a view as a child. Children views are stored at this.children, and destroyed when the parent is destroyed. Returns the child for chaining.

Kind: instance method of View

Param Type
child Rasti.View

view.destroyChildren()

Call destroy method on children views.

Kind: instance method of View

view.ensureElement()

Ensure that the view has a root element at this.el. You shouldn't call this method directly. It's called from the constructor. You may override it if you want to use a different logic or to postpone element creation.

Kind: instance method of View

view.createElement(tag, attributes) ⇒ node

Create an element. Called from the constructor if this.el is undefined, to ensure the view has a root element.

Kind: instance method of View
Returns: node - The created element.

Param Type Default Description
tag string "div" Tag for the element. Default to div
attributes object Attributes for the element.

view.removeElement() ⇒ Rasti.View

Remove this.el from the DOM.

Kind: instance method of View
Returns: Rasti.View - Return this for chaining.

view.delegateEvents([events]) ⇒ Rasti.View

Provide declarative listeners for DOM events within a view. If an events object is not provided, it defaults to using this.events. If this.events is a function, it will be called to get the events object.

The events object should follow the format {'event selector': 'listener'}:

  • event: The type of event (e.g., 'click').
  • selector: A CSS selector to match the event target. If omitted, the event is bound to the root element.
  • listener: A function or a string representing a method name on the view. The method will be called with this bound to the view instance.

By default, delegateEvents is called within the View's constructor. If you have a simple events object, all of your DOM events will be connected automatically, and you will not need to call this function manually.

All attached listeners are bound to the view, ensuring that this refers to the view object when the listeners are invoked. When delegateEvents is called again, possibly with a different events object, all previous listeners are removed and delegated afresh.

The listeners will be invoked with the event and the view as arguments.

Kind: instance method of View
Returns: Rasti.View - Returns this for chaining.

Param Type Description
[events] object Object in the format {'event selector' : 'listener'}. Used to bind delegated event listeners to the root element.

Example

// Using a function.
class Modal extends View {
    events() {
        return {
            'click button.ok': 'onClickOkButton',
            'click button.cancel': function() {}
        };
    }
}

// Using an object.
Modal.prototype.events = {
    'click button.ok' : 'onClickOkButton',
    'click button.cancel' : function() {}
};

view.undelegateEvents() ⇒ Rasti.View

Removes all of the view's delegated events. Useful if you want to disable or remove a view from the DOM temporarily. Called automatically when the view is destroyed and when delegateEvents is called again.

Kind: instance method of View
Returns: Rasti.View - Return this for chaining.

view.render() ⇒ Rasti.View

Renders the view.
This method should be overridden with custom logic. The only convention is to manipulate the DOM within the scope of this.el, and to return this for chaining.
If you add any child views, you should call this.destroyChildren before re-rendering.
The default implementation updates this.el's innerHTML with the result of calling this.template, passing this.model as the argument.

Security Notice: The default implementation utilizes innerHTML, which may introduce Cross-Site Scripting (XSS) risks.
Ensure that any user-generated content is properly sanitized before inserting it into the DOM. You can use the View.sanitize static method to escape HTML entities in a string.
For best practices on secure data handling, refer to the OWASP's XSS Prevention Cheat Sheet.

Kind: instance method of View
Returns: Rasti.View - Returns this for chaining.

View.sanitize(str) ⇒ string

Escape HTML entities in a string. Use this method to sanitize user-generated content before inserting it into the DOM. Override this method to provide a custom escape function. This method is inherited by Component and used to escape template interpolations.

Kind: static method of View
Returns: string - Escaped string.

Param Type Description
str string String to escape.