Crate custom_elements

The Web Components standard creates a browser feature that allows you to create reusable components, called Custom Elements.

While web_sys exposes the browser’s CustomElementRegistry interface, it can be hard to use. Creating a Custom Element requires calling customElements.define() and passing it an ES2015 class that extends HTMLElement, which is not currently possible to do directly from Rust.

This crate provides a CustomElement trait that, when implemented, allows you to encapsulate any Rust structure as a reusable web component without writing any JavaScript. In theory it should be usable with any Rust front-end framework.

impl CustomElement for MyWebComponent {
  fn inject_children(&mut self, this: &HtmlElement) {
      inject_style(&this, "p { color: green; }");
      let node = self.view();
      this.append_child(&node).unwrap_throw();
  }

  fn observed_attributes() -> &'static [&'static str] {
      &["name"]
  }

  fn attribute_changed_callback(
      &mut self,
      _this: &HtmlElement,
      name: String,
      _old_value: Option<String>,
      new_value: Option<String>,
  ) {
      if name == "name" {
          /* do something... */
      }
  }

  fn connected_callback(&mut self, _this: &HtmlElement) {
      log("connected");
  }

  fn disconnected_callback(&mut self, _this: &HtmlElement) {
      log("disconnected");
  }

  fn adopted_callback(&mut self, _this: &HtmlElement) {
      log("adopted");
  }
}

#[wasm_bindgen]
pub fn define_custom_elements() {
    MyWebComponent::define("my-component");
}

Statics

• HtmlElementConstructor

Traits

• CustomElement
  A custom DOM element that can be reused via the Web Components/Custom Elements standard.

Functions

• inject_style
  Attaches a <style> element with the given content to the element, either to its shadow root (if it exists) or to the custom element itself.
• inject_stylesheet
  Attaches a <link rel="stylesheet"> element with the given URL to the custom element, either to its shadow root (if it exists) or to the custom element itself.