Optimizing your Angular application’s performance often involves understanding how components render and update. A common scenario arises when you have UI elements or complex calculations that only need to happen once during the component’s lifecycle. These are often referred to as “one-time” or “fire-and-forget” components or rendering patterns.
Standard Angular change detection is powerful, but it can sometimes lead to unnecessary work within components whose content or state is determined solely at the time of their initial creation. For elements that display static data or the result of an initial computation that won’t change, repeated checks by the change detection system are wasteful.
To effectively implement these one-time rendering patterns, you can leverage Angular’s built-in capabilities to control when and how components are initialized and updated. The key is to structure your templates and component logic to prevent subsequent updates after the initial render.
One powerful technique involves using structural directives like *ngIf or variations of *ngFor. By binding these directives to a condition that is only true initially or is determined once, you ensure the component or template block is created and rendered only a single time. After that initial phase, the condition becomes false or the loop completes its one-time iteration, and Angular knows not to revisit that section for updates.
For instance, displaying a block of static content or the result of a complex calculation performed in ngOnInit can be wrapped in an *ngIf tied to a flag that is set to true in ngOnInit and never changes back. Similarly, iterating over a list that is loaded once can sometimes be optimized if the rendering within the loop is heavy and static per item.
Implementing these patterns correctly can lead to significant performance improvements, especially in large, data-rich applications. It reduces the workload on the change detection system, resulting in faster render times and a more responsive user interface. By deliberately controlling the lifecycle of specific UI parts, you build a more efficient and maintainable application architecture. Mastering these techniques is essential for high-performance Angular development.
Source: https://itnext.io/show-it-once-then-never-again-one-time-ui-in-angular-4ff727fef96e?source=rss—-5b301f10ddcd—4
