Introducing Lightning Web Components
Salesforce is committed to developing open web standards and is a member of the World Wide Web Consortium (W3C). Salesforce Lightning Web Components.
Base Lightning components are available as Aura components and as Lightning web components. The Component Reference includes documentation, specifications, and examples for both. See Base Components: Aura Vs Lightning Web Components for differences between them.
Create Lightning Web Components
A Lightning web component is a reusable custom HTML element with its own API.
Define a Component
To style components, use Lightning Design System or CSS.
Reactivity is a system at the core of the Lightning Web Components framework. The framework observes changes to the values of fields and properties. When it observes a change, it reacts. It reevaluates all the expressions used in the template and rerenders the component, which displays the new values.
You can add components within the body of another component. Composition enables you to build complex components from simpler building-block components.
Fields, Properties, and Attributes
Access Static Resources, Labels, Internationalization Properties, User IDs, and Form Factors
Lightning components can access global Salesforce values, such as labels, resources, and users.
Accessible software and assistive technologies enable users with disabilities to use the products you build. Develop your components so that all users can perceive, understand, navigate, and interact with them.
Lightning web components have a lifecycle managed by the framework. The framework creates components, inserts them into the DOM, renders them, and removes them from the DOM. It also monitors components for property changes. Generally, components don’t need to call these lifecycle hooks, but it is possible.