ts-strictify

Runs TypeScript with strict-related flags and reports errors only for files you changed.

Background

Enabling TypeScript strictness in an existing codebase is often an “all or nothing” change: tsc will report errors across the entire project, even if you only touched a couple of files.

ts-strictify is meant for incremental adoption. It runs tsc with strict-related flags and filters the compiler output down to:

• .ts / .tsx files you changed compared to a target branch
• optionally also staged/modified/untracked/created files in your working tree

How it works

When you start working on a new feature or fixing a bug, you will modify the code base in one way or another. ts-strictify will take a look at these changes - and only these changes (!) and will complain, if the files you have touched are not strict compliant.

This is different from how TypeScript normally works. You could check a single file against the compiler, but the compiler would also look up the imports and the imports of the imports. Not exactly what you want when you are looking for an incremental upgrade path.

Head over to https://cschroeter.net/moving-to-strict-typescript/ for more insights.

Install

Requirements:

• Node.js >=21
• typescript >=5 <7 (peer dependency)

With npm:

npm install --save-dev @ttsvetko/ts-strictify typescript

Usage

With npx (after installing):

npx ts-strictify

Without installing:

npx @ttsvetko/ts-strictify

With npm:

1. Add "ts-strictify": "ts-strictify" to the scripts section of package.json.
2. npm run ts-strictify

Pre-Commit Hook

You can run ts-strictify as a pre-commit hook using husky.

npm install --save-dev husky

Then create a pre-commit hook that runs npx ts-strictify (see Husky’s docs for the current setup steps).

Options

Options:
  --help                          Show help                            [boolean]
  --version                       Show version number                  [boolean]
  --noImplicitAny                                 [boolean] [default: true]
  --noImplicitThis                                     [boolean] [default: true]
  --noImplicitUseStrict                               [boolean] [default: false]
  --alwaysStrict                                       [boolean] [default: true]
  --strictBindCallApply                                [boolean] [default: true]
  --strictNullChecks                                   [boolean] [default: true]
  --strictFunctionTypes                                [boolean] [default: true]
  --strictPropertyInitialization                       [boolean] [default: true]
  --noEmit                                             [boolean] [default: true]
  --targetBranch                                    [string] [default: "master"]
  --commitedFiles                                      [boolean] [default: true]
  --stagedFiles                                        [boolean] [default: true]
  --modifiedFiles                                      [boolean] [default: true]
  --untrackedFiles                                     [boolean] [default: true]
  --createdFiles                                       [boolean] [default: true]

Note: --targetBranch defaults to "master" for historical compatibility; many repos use "main" (use --targetBranch main).

Supported SCM

• Git