reference-compiler-cli

The Angular compiler CLI integrates with TypeScript by wrapping the TypeScript program to support Angular decorators and template processing during standard type checking. It coordinates compilation phases through core subsystems like NgtscProgram and NgCompiler without replacing the TypeScript compiler.

TraitCompiler and DecoratorHandlers in ngtsc identify Angular decorators on classes and apply specific compilation logic to them. They work together during the analysis phase to transform decorated classes into Angular-compatible code.

Incremental analysis in the Angular compiler CLI is performed on demand with caching and selective re-analysis. You reason about compilation phases by tracking dependencies across subsystems, ensuring that only modified files trigger re-evaluation during emit.

Yes, understanding the ngtsc architecture allows you to safely modify Angular template type checking. The compiler CLI coordinates type checking through dedicated subsystems that interact with the TypeScript compiler to validate template expressions.

The best way to understand the ngtsc program and compiler lifecycle is to review the high-level architecture overview of its core subsystems. This mental model explains how analysis and emit phases coordinate safely.

The Angular compiler performs lazy evaluation during the analysis phase to optimize compilation performance. By using caching and on-demand processing, it avoids redundant work and ensures selective re-analysis only when dependencies change.