ts-helper
This is a simple TypeScript tool we use at Glide for two purposes so far:
- It finds cyclic imports in our source files. We used to
use ESLint's
import/no-cycle rule
for this, but on our project it's both very slow and sometimes doesn't find existing cycles.
- It outputs a dependency graph of all the TypeScript source files in our project which we can use for further
analysis.
Caveats
We've only implemented as much as we needed to make this work on our codebase, so there might be cases it doesn't
support, or on which it crashes on. If you run into such a case, please considering sending us a PR, or at least report
the issue with a reproduction.
A few of the things that are missing, in particular:
- We don't respect
exclude in the project configuration.
- We only look at
import (and export), not require.
- We treat type import calls such as
type X = import("foo").Bar as regular "strong" imports.
Usage
-p|--project TS-PROJECT
Adds a project. TS-PROJECT can be either a directory with a tsconfig.json file in it, or the path to a TypeScript
config file. ts-helper will add project references recursively, but you can add more than one root project if you need
to.
-r|--root SOURCE-FILE
Adds a root TypeScript source file. This file must be in one of the specified projects. You can add more than one.
-c|--detect-cycles
Runs cycle detection on all the source files reachable from the roots. If it detects a cycle it will print one of the
cycles it found and exit with an error status.
Note that it only considers "strong" imports for cycle detection, vs type imports and lazy imports.
-o|--output FILENAME
Outputs a JSON file with the dependency graph.
-v|--verbose
Print messages when it's reading and processing projects.
Example
In our main repository for Glide we have two TypeScript projects - one for the frontend and one for the backend. The
frontend one has one root source file and the backend has two - one for the actual backend and one for a CLI. Here's how
we run ts-helper to detect cycles in that codebase:
npx "@glideapps/ts-helper" \
-p ~/Work/glide/functions \
-r ~/Work/glide/functions/src/cli.ts \
-r ~/Work/glide/functions/src/index.ts \
-p ~/Work/glide/app \
-r ~/Work/glide/app/src/index.tsx \
-c
