What is JIT?

Just-in-Time (JIT) is a type of compilation that compiles your app in the browser at runtime. JIT compilation was the default until Angular 8, now default is AOT. When you run the ng build (build only) or ng serve (build and serve locally) CLI commands, the type of compilation (JIT or AOT) depends on the value of the aot property in your build configuration specified in angular.json. By default, aot is set to true.

Practical Code Example

// JIT (Just-In-Time) Compilation:
// Browser downloads Angular compiler (~1MB) along with source code,
// and compiles templates dynamically in the browser at runtime.