https://github.com/soontao/cycle-import-check
JS module circular dependency check tool
https://github.com/soontao/cycle-import-check
es6-javascript import static-check
Last synced: 8 months ago
JSON representation
JS module circular dependency check tool
- Host: GitHub
- URL: https://github.com/soontao/cycle-import-check
- Owner: Soontao
- License: mit
- Created: 2018-06-14T06:35:49.000Z (over 7 years ago)
- Default Branch: main
- Last Pushed: 2025-04-30T15:13:00.000Z (8 months ago)
- Last Synced: 2025-04-30T21:09:38.747Z (8 months ago)
- Topics: es6-javascript, import, static-check
- Language: TypeScript
- Homepage:
- Size: 1.48 MB
- Stars: 22
- Watchers: 2
- Forks: 6
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# 
cycle-import-check
> circular dependency check tool for javascript modules
[](https://github.com/Soontao/cycle-import-check/actions?query=workflow%3A%22Multi-Version+Test%22)
[](https://codecov.io/gh/Soontao/cycle-import-check)
[](https://www.npmjs.com/package/cycle-import-check)
ES6 circular import check tool, support `js`, `ts`, `jsx`, `tsx` and `mjs` files, and will ignore all `node_modules` files.
Support `import`, `export` keywords and `require()`, `import()` function now
## Why do we need this tool ?
In javascript ES6 standard, people use `import` & `export` keyword in modules, but if js files circular import each other, some exported objects will be `undefined` in runtime.
The best practice is **one-way dependency**, and I wrote this tool to ensure no circular-dependency in projects.
## Circular dependency sample project
Let's look at a circular dependency example:
> file1.js
```javascript
// and console will be first triggered in file2
import { value2 } from "./file2";
// file2 is fully imported
export const value1 = "value1"
// value2 is 'value2'
console.log("value2 in file1: " + value2)
setTimeout(() => {
// value2 is 'value2'
console.log("delay 200ms, value2 in file1: " + value2)
}, 200)
// file1 is fully executed now
```
> file2.js
```javascript
import { value1 } from "./file1";
// file1 is not fully executed, just ref with cache
export const value2 = "value2"
// value1 is undefined
console.log("value1 in file2: " + value1)
setTimeout(() => {
// file1 is executed now
console.log("delay 200ms, value1 in file2: " + value1) // value1 is 'value1'
}, 200)
```
```bash
> babel-node --presets es2015 file1.js
value1 in file2: undefined
value2 in file1: value2
delay 200ms, value1 in file2: value1
delay 200ms, value2 in file1: value2
```
If we only have two js files, it's easy to determine wether scripts have circular dependencies.
However, if we have a large project with thousands of files, it's hard to do that.
So, this tool appeared, using old (but efficient) graph algorithms to check for circular dependency.
## How to resolve circular dependency ?
Just extract shared variables/functions into an independent file:
`from`
```mermaid
graph TD
file1.js -->|value1| file2.js
file1.js -->|value2| file2.js
```
`to`
```mermaid
graph TD
file1.js -->|value1| value.js
file2.js -->|value2| value.js
```
## Usage
```bash
npx cycle-import-check [a directory path]
```
> detected
```text
> iscan tests/testproject4
Circular dependency existed in tests/testproject4
cycle 1, size (2):
tests/testproject4/file2.js
tests/testproject4/file1.js
```
> normal
```text
> iscan tests/testproject2
Congratulation! Not found circular dependency in tests/testproject2
```
## [CHANGELOG](./CHANGELOG.md)
## [LICENSE (MIT)](./LICENSE)