TypeScript Incremental Builds with tsBuildInfoFile

TypeScript recompiles the entire project on every tsc invocation even when only one file changed, making build times grow linearly with project size.

Enable 'incremental: true' to cache build information and skip unchanged files.

// tsconfig.json
{
  "compilerOptions": {
    "incremental": true,
    "tsBuildInfoFile": "./.tsbuildinfo"
  }
}

# First build: full compile, creates .tsbuildinfo
tsc

# Second build: only changed files recompiled
tsc  # Much faster

# In .gitignore
echo ".tsbuildinfo" >> .gitignore

# For --noEmit with incremental:
tsc --noEmit --incremental --tsBuildInfoFile .tsbuildinfo

// package.json
{
  "scripts": {
    "typecheck": "tsc --noEmit --incremental --tsBuildInfoFile .tsbuildinfo",
    "build": "tsc --build"
  }
}

The .tsbuildinfo file stores a fingerprint of each file's content and its resolved types. On subsequent builds, TypeScript skips files whose fingerprints match, only recompiling changed files and their dependents.