The --incremental flag in TypeScript is a significant feature designed to optimize the compilation process by reducing the time it takes to recompile projects. This flag is particularly useful in large projects where full compilation can be time-consuming.
Purpose of the --incremental Flag
Faster Subsequent Builds:
The primary purpose of the --incremental flag is to speed up the build process after the initial compilation. When this flag is enabled, TypeScript saves information about the project graph from the last compilation into a file (typically named .tsbuildinfo). This information includes details about the file structure and the dependencies of the project[1][3][6][7].
Efficient Compilation:
On subsequent compilations, TypeScript uses the saved information to perform an incremental build. This means it only recompiles parts of the project that have changed since the last build, rather than recompiling the entire project. This selective recompilation significantly reduces the build time[1][3][6][7].
Usage in Development:
During development, where frequent changes are made to the codebase, the --incremental flag can drastically reduce the wait time for changes to be reflected in the output, enhancing developer productivity[3][6].
Technical Implementation
When the --incremental flag is used, TypeScript checks for the .tsbuildinfo file. If it exists, TypeScript will use the data from this file to skip the type checking and emitting phases for unchanged files, thus only processing the changed files[1][3][7].
The .tsbuildinfo file contains hashes of the file contents and compiler set...
