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Introduction to Web Components and Medblocks UI

Medblocks UI is built using LIT, a framework for web components. Here are some basic concepts to understand how to use these elements.

For a list of all web components available and their properties, attributes, and events, please visit Components Section or the Github documentation.

Attributes and Properties​

When you import medblocks-ui, multiple custom elements get registered in your browser. This allows the usage of elements that are not covered in the base HTML specification:

<mb-input label="Hello there"></mb-input>

The behavior of these elements can be configured using attributes and properties. Attributes: Are what you see represented in the HTML code. Eg: label="Hello there" Properties: What you can programmatically set using Javascript on an element. Eg: Select the element, and do $0.label = "Hello there" Most attributes in Medblocks UI also have a corresponding property, but not all properties, have an attribute of the same name. For example, if you want to set the ctx on mb-form, you'll have to use a property because you need to pass an Object:

<mb-form> </mb-form>
<script>
  document.querySelector("mb-form").ctx = { composer: "Dr. Bean" };
</script>

Using <mb-form ctx="{'hello': 'there'}"> does NOT work, because attributes can only pass strings.

However, in most modern frameworks, this issue has been addressed.

In Vue:​

<template>
  <mb-form :ctx.prop="data"></mb-form>
</template>

In Svelte:​

<mb-form ctx="{data}" />

For a more definite list of how to set properties and attributes in your favorite framework, check out the Custom Elements Everywhere website.

Listening to events​

Just like normal HTML elements, custom elements emit events. These are Custom Events and can be listened to by using the same event listeners:

<mb-form id="form">
  <mb-input path="name" label="What's your name?"></mb-input>
  <mb-submit>
    <button>Submit</button>
  </mb-submit>
</mb-form>

<script>
  // Pure javascript version of JQuery's $('document').ready
  document.addEventListener("DOMContentLoaded", () => {
    var form = document.getElementById("form");
    // Listen for mb-submit event
    form.addEventListner("mb-submit", (event) => {
      console.log(event.detail);
    });
  });
</script>

However, most frameworks have a sophisticated way to listen to events.

In Vue:​

<mb-form id="form" @mb-submit="handleEvent">
  <mb-input path="name" label="What's your name?"></mb-input>
  <mb-submit>
    <button>Submit</button>
  </mb-submit>
</mb-form>

In Svelte:​

<mb-form id="form" on:mb-submit="handleEvent">
  <mb-input path="name" label="What's your name?" />
  <mb-submit>
    <button>Submit</button>
  </mb-submit>
</mb-form>

For a more definite list of how to listen to events in your favorite framework, check out the Custom Elements Everywhere website.