Build Strict tsconfig & Compiler Boundaries as a system involving module resolution, runtime validation, declaration output, incremental builds, CI, and package boundaries—not only a compiler concern. Remember that TypeScript types are erased at runtime.
Build a Complete Mental Model
Build Strict tsconfig & Compiler Boundaries as a system involving module resolution, runtime validation, declaration output, incremental builds, CI, and package boundaries—not only a compiler concern. Remember that TypeScript types are erased at runtime.
Apply It in Production TypeScript
Type-check an original Strict tsconfig & Compiler Boundaries example in strict mode, then test valid values, null/undefined, malformed API data, a new union variant, and module boundaries. Fix the contract or validation instead of silencing errors with assertions or any.
After This Lesson
{
"compilerOptions": {
"strict": true,
"module": "esnext",
"target": "es2025",
"noUncheckedIndexedAccess": true,
"exactOptionalPropertyTypes": true,
"noEmit": true
},
"include": ["src/**/*.ts"]
}Strict checks catch unsafe assumptions before runtime.Try It Yourself
Type-check an original Strict tsconfig & Compiler Boundaries example in strict mode, then test valid values, null/undefined, malformed API data, a new union variant, and module boundaries. Fix the contract or validation instead of silencing errors with assertions or any.
Type Safety Warning
Assuming a successful TypeScript compile proves API data and runtime behavior are valid.
TypeScript Compiler Options — TypeScript