Angular Ivy is the new rendering engine for Angular, introduced in Angular version 9. It replaces the previous rendering engine, known as View Engine. Ivy has been designed to provide significant improvements in terms of application build size, performance, and better flexibility for future improvements to the Angular framework.
There are three main aspects in which Ivy improves application build size and performance:
1. Tree-shakable libraries and components: Ivy generates simpler instruction sets that are more in line with modern JavaScript standards. This makes Angular code easier to be processed by tree-shaking techniques. Tree-shaking is a process in which unused code in your application is eliminated, leading to smaller bundle sizes.
2. Localization support: Ivy improves how localization, the process of adapting a product to different languages and cultural differences, is handled. Instead of including localization logic in each build, Angular Ivy compiles the code once, and then translation files can be applied separately, reducing the overall build size.
3. Incremental builds and compilation: Ivy’s architecture allows Angular to compile one component at a time without the need for global metadata. This enables incremental compilation, which greatly reduces the build time, since only the changed components need to be recompiled. Effective caching mechanisms can also be used for builds where most components have not been updated.
Let’s consider an example of how Ivy reduces the build size. Suppose you have a simple Angular application with two components, ‘ComponentA‘ and ‘ComponentB‘. In Angular with View Engine, these components would generate complex code and metadata, even if these components are not using most of the Angular features.
With Ivy, the generated code for the components will be simpler and will only include instructions for the features that the components are actually using. The improvements in tree-shaking will lead to the elimination of the unused code, resulting in a smaller final build size.
In terms of performance, assume that you have a large Angular application with hundreds of components. With the View Engine, changing a single component requires the entire application to be compiled because of the global metadata involved. With Ivy, only the changed component will be recompiled, leading to faster incremental builds.
In summary, Angular Ivy improves application build size and performance by:
- Generating simpler, tree-shakable code, reducing bundle sizes.
- Improving localization support leading to smaller build sizes.
- Enabling incremental builds, which improve compilation time.
These improvements make Angular applications lighter, faster, and more efficient, leading to a better overall user experience.