Key Differences between Aura and LWC

1. Technology Basis:
   • LWC is built on modern web standards like native JavaScript, HTML, and CSS.
   • Aura uses a proprietary Salesforce framework and does not fully leverage web standards.
2. Performance:
   • LWC is more lightweight and faster because it uses browser-native APIs, resulting in better performance.
   • Aura can be slower since it requires more processing and abstraction.
3. Development Complexity:
   • LWC is easier to learn and develop with because it uses standard JavaScript and web technologies.
   • Aura has a steeper learning curve with its own component model and syntax.
4. Component Composition:
   • LWC allows for better modularity and encapsulation with the Shadow DOM, leading to more reusable and isolated components.
   • Aura components can interfere with each other, as there is no native encapsulation like Shadow DOM.
5. Reactivity:
   • LWC uses reactive data binding, meaning the UI automatically updates when data changes.
   • Aura requires manual re-rendering or complex boilerplate code to update UI.
6. File Structure:
   • LWC has a clean and simple file structure, with HTML, JavaScript, and CSS bundled per component.
   • Aura components have more complex structures and files, making them harder to manage.
7. Locker Service:
   • LWC is natively built with the Locker Service in mind, making it more secure by default.
   • Aura requires additional handling for Locker Service compliance, which can sometimes limit functionality.
8. Browser Support:
   • LWC supports modern browsers but does not support older ones.
   • Aura has better backward compatibility with older browsers, though this advantage is becoming less relevant.

1. Component Declaration:

1. Aura: Components are defined with .cmp files.
2. LWC: Components are defined with standard .html and .js files.

2. JavaScript Controller:

1. Aura: We have to define controllers in a separate .js file and must follow Aura-specific patterns.
2. LWC: We can use standard JavaScript ES6 modules with reactive binding (@api, @track).

Aura Syntax

({
    handleClick: function(component, event, helper) {
        alert("Button clicked in Aura");
    }
})
  

LWC Syntax

import { LightningElement } from 'lwc';

export default class MyComponent extends LightningElement {
    handleClick() {
        alert("Button clicked in LWC");
    }
}
  

3. Attributes vs Properties:

1. Aura: Uses aura:attribute to define data bindings.
2. LWC: Uses decorators like @api and @track for reactive properties.

LWC Syntax

import { LightningElement, api } from 'lwc';

export default class MyComponent extends LightningElement {
    @api myProperty = 'LWC Property';
}
  

4. Data Binding:

1. Aura: Data binding is done via {!} syntax.
2. LWC: Data binding uses {} and is more reactive, as it leverages standard JavaScript bindings.

LWC JavaScript

export default class MyComponent extends LightningElement {
    greeting = 'Hello, LWC!';
}
  

5. Event Handling:

1. Aura: Custom events are fired and handled using aura:registerEvent and c.fire.
2. LWC: Events are handled using standard DOM events (dispatchEvent).

LWC Syntax

const event = new CustomEvent('myevent', {
    detail: { message: 'Hello, LWC!' }
});

this.dispatchEvent(event);
  

6. Base Components:

1. Aura: Uses <lightning:componentName>.
2. LWC: Imports standard components using import and tags like <lightning-button>.