The connectedCallback { } method is a technique that can run custom logic when a Lightning web component is loaded. The connectedCallback { } method is a lifecycle hook that is invoked when a component is inserted into the DOM. The connectedCallback { } method can be used to perform any initialization tasks, such as fetching data, setting attributes, or registering event listeners. By using the connectedCallback { } method, the developer can run the custom logic when the component is loaded, and ensure that the component is ready to render and interact with the user. Reference: [connectedCallback Hook], [Lightning Web Components Lifecycle Hooks]