A tool for migrating frontend application from JavaScript to TypeScript
npm install ts-migratets-migrate is a tool for migrating frontend application to TypeScript.
Run npx ts-migrate to convert your frontend application to TypeScript.
ts-migrate is designed around Airbnb projects. Use at your own risk.
Install ts-migrate using npm:
npm install --save-dev ts-migrate
Or yarn:
yarn add --dev ts-migrate
Migrate an entire project like this:
``sh`
npx -p ts-migrate -c "ts-migrate-full
Please note that it may take a long time to do a full migration.
You can also migrate individual parts of a project by specifying a subset of sources:
`sh`
npx ts-migrate-full
--sources="relative/path/to/subset/*/" / # list the subset to migrate,
--sources="node_modules/*/.d.ts" # including any global types that the
# migrator may need to know about.
Or, you can run individual CLI commands:
`
$ npx ts-migrate -- --help
npm run ts-migrate --
Commands:
npm run ts-migrate -- init
npm run ts-migrate -- rename
npm run ts-migrate -- migrate
npm run ts-migrate -- reignore
* These commands can be passed a --sources (or -s) flag. This flag accepts a relative
path to a subset of your project as a string (glob patterns are allowed). When this flag
is used, ts-migrate ignores your project's default source files in favor of the ones
you've listed. It is effectively the same as replacing your tsconfig.json's include
property with the provided sources. The flag can be passed multiple times.
Options:
-h, -- help Show help
-i, -- init Initialize TypeScript (tsconfig.json) in
-m, -- migrate Fix TypeScript errors, using codemods
-rn, -- rename Rename files in
-ri, -- reignore Re-run ts-ignore on a project
Examples:
npm run ts-migrate -- --help Show help
npm run ts-migrate -- init frontend/foo Create tsconfig.json file at frontend/foo/tsconfig.json
npm run ts-migrate -- rename frontend/foo Rename files in frontend/foo from JS/JSX to TS/TSX
`
If you are in a situation where you made some big project-wise changes, update of the common library like TypeScript, React or Redux or improve types for the large codebase. As a result of these operations, you might get quite a few TypeScript compilation errors. There are two ways to proceed:
1) Fix all the errors (ideal, but time-consuming).
2) Make the project compilable and fix errors gradually.
For the second option we created a re-ignore script, which will fully automate this step. It will add any or @ts-expect-error (@ts-ignores) comments for all problematic places and will make your project compilable.
Usage: npx ts-migrate -- reignore.
for partial migrationsThere are times in which migrating an entire project is too large a change. The --sources flag (or -s for short) allows you to run ts-migrate on a subset of your project by providing a set of sources to override the defaults specified in your tsconfig. --sources takes a relative path from the root of your project. It accepts globs, but remember to wrap any globs with quotes.
`shRun everything on a sub-directory
npx ts-migrate-full /path/to/your/project --sources "some/components/*/"
Because your project's default sources are ignored when
is used, it's a good idea to specify any ambient type files your project uses as well. Otherwise, ts-migrate might mark unidentifiable globals as type errors, even when they aren't. For example, re-including ambient types from your node_modules folder looks like this:`sh
npx ts-migrate-full /path/to/your/project \
--sources "some/components/*/" \
--sources "node_modules/*/.d.ts"
`FAQ
> Can it magically figure out all the types?
Unfortunately, no, it is only so smart. It does figure out types from propTypes, but it will fall back to
($TSFixMe) for things it can't figure it out.
> I ran ts-migrate on my code and see lots of
@ts-expect-error (@ts-ignores) and any. Is that expected?The ts-migrate codemods are only so smart. So, follow up is required to refine the types and remove the
any ($TSFixMe) and @ts-expect-error (@ts-ignores). The hope is that it's a nicer starting point than from scratch and that it helps accelerate the TypeScript migration process.
> Um... ts-migrate broke my code! D:
Please file the issue here.
> What is
$TSFixMe?It's just an alias to
any: type $TSFixMe = any;. We use it at Airbnb for simplifying the migration experience.
We also have the same alias for functions: type $TSFixMeFunction = (...args: any[]) => any;`.
> How did you use ts-migrate?
It was used a lot at Airbnb codebase! With the help of the ts-migrate we were able to migrate the main part of the entire codebase to the TypeScript. We were able to provide much better starting points in the migration for the huge applications (50k+ lines of codes) and they were migrated in one day!
> Is ts-migrate framework-oriented?
By itself, ts-migrate is not related to any framework. We created a set of plugins, which are related to the React (link to react). So, default configuration(link) contains plugins, which are expecting a react codebase as an input. We didn't test it on any other frameworks or libraries, use at your own risk!
See the Contributors Guide.