rev-dep
File dependency debugging tool for TypeScript projects
Pardon 🤫
Since you landed here, you might be also interested in my other project - supercharged multiline code search and replace tool - codeque.co 🥳
About 📣
The tool was created help with daily dev struggles by answering these questions:
👉 What entry points my codebase have
👉 Which entry points uses a given file
👉 Which dependencies a given file has
This helps to debug project dependencies, plan refactoring, optimize bundles or plan code splitting.
It's especially useful in JS world without TypeScript or tests coverage.
It also helps to identify and eliminate dead files, understand the complexity of the file dependencies
🦘 Jump to CLI reference
🕸️ export * from
problem
Use cases 🧑💻
How about dependency or bundle graphs?
There are tool that can output nice, visual representation of project dependencies like webpack-bundle-analyzer or dependency-cruiser (which btw rev-dep uses for non-TS codebases)
While graphs can be useful to identify major problems like too big bundle size or to visualize mess in your deps, it's hard to take any action based on them (at least it was hard for me 🤷♂️)
rev-dep
visualize dependencies as lists, so it's really easy to see where to cut the line to solve the problem.
Getting Started 🎉
Install globally to use as CLI tool
yarn global add rev-dep
or
npm -g install rev-dep
Install in project to use as a module
yarn add rev-dep
or
npm install rev-dep
Recipes 🌶️
How to identify where a file is used in the project?
Just use rev-dep resolve path/to/file.ts
You will see all the entry points that implicitly require given file together with resolution path.
resolve
Command CLI reference
Example for the rev-dep repository
command:
rev-dep resolve src/lib/utils.ts
output:
src/babel/index.js :
➞ src/babel/index.js
➞ src/lib/utils.ts
_____________________
src/cli/index.ts :
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/find.ts
➞ src/lib/getDepsTree.ts
➞ src/lib/getDepsSetWebpack.ts
➞ src/lib/utils.ts
_____________________
Getting more details about file resolution in given entry point
To find out all paths combination use rev-dep resolve
with -a
flag
You might be surprised how complex dependency tree can be!
Example for the rev-dep repository
command:
rev-dep resolve src/lib/utils.ts src/cli/index.ts --all
output:
src/cli/index.ts :
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/find.ts
➞ src/lib/getDepsTree.ts
➞ src/lib/getDepsSetWebpack.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/find.ts
➞ src/lib/getEntryPoints.ts
➞ src/lib/getDepsTree.ts
➞ src/lib/getDepsSetWebpack.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/entryPoints/index.ts
➞ src/lib/getEntryPoints.ts
➞ src/lib/getDepsTree.ts
➞ src/lib/getDepsSetWebpack.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/files/index.ts
➞ src/lib/getDepsTree.ts
➞ src/lib/getDepsSetWebpack.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/find.ts
➞ src/lib/getEntryPoints.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/entryPoints/index.ts
➞ src/lib/getEntryPoints.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/find.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/resolve/index.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/entryPoints/index.ts
➞ src/lib/utils.ts
➞ src/cli/index.ts
➞ src/cli/createCommands.ts
➞ src/cli/files/index.ts
➞ src/lib/utils.ts
How to check if a file is used in the project?
Use rev-dep resolve path/to/file.ts --compactSummary
As a result you will see total amount of entry points requiring a given file.
Note that among the entry points list there might be some dead files importing the searched file
resolve
Command CLI reference
Example for the rev-dep repository
command:
rev-dep resolve src/lib/utils.ts --compactSummary
output:
Results:
__tests__/find.test.js : 0
babel.js : 0
bin.js : 0
scripts/addDocsToReadme.js : 0
src/babel/index.js : 1
src/cli/index.ts : 1
src/lib/getMaxDepthInGraph.ts : 0
types.d.ts : 0
Total: 2
How to identify dead files in the project?
Use rev-dep entry-points
to get list of all files that are not required by any other files in the project.
You might want to exclude some file paths that are meant to be actual entry point like index.js
or **/pages/**
in next.js
projects using --exclude
flag. The same for configuration files like babel.config.js
Review the list and look for suspicious files like src/ui/components/SomeComponent/index.js
entry-points
command CLI reference
Example for the rev-dep repository
command:
rev-dep entry-points --exclude '__tests__/**' 'types.d.ts'
output:
babel.js
bin.js
scripts/addDocsToReadme.js
src/babel/index.js
src/cli/index.ts
src/lib/getMaxDepthInGraph.ts
The last one src/lib/getMaxDepthInGraph.ts
is the source file that is not used at the moment.
The rest of them looks legit!
How to check which files are imported by a given file?
To get a full list of files imported by given entry point use rev-dep files path/to/file.ts
.
You can use --count
flag if you are interested in the amount.
This is a good indicator of how heavy a given entry point or component is
files
command CLI reference
Example for the rev-dep repository
command:
rev-dep files files src/cli/index.ts
output:
src/cli/index.ts
src/cli/createCommands.ts
package.json
src/cli/resolve/index.ts
src/cli/docs/index.ts
src/cli/entryPoints/index.ts
src/cli/files/index.ts
src/lib/find.ts
src/cli/resolve/types.ts
src/cli/resolve/formatResults.ts
src/lib/utils.ts
src/cli/commonOptions.ts
src/cli/docs/generate.ts
src/cli/entryPoints/types.ts
src/lib/getEntryPoints.ts
src/lib/buildDepsGraph.ts
src/cli/files/types.ts
src/lib/getDepsTree.ts
src/lib/types.ts
src/cli/docs/template.ts
src/lib/getDepsSetWebpack.ts
src/lib/cleanupDpdmDeps.ts
As you can see cli even import package.json
. This is to print version of the cli
How to reduce amount of files imported by entry point?
There is no easy how to for this process, but you can do it iteratively using rev-dep
commands files
and resolve
-
Get the list of files imported by entry-point
rev-dep files path/to/entry-point
-
Identify some suspicious files on the list, components that should not be used on the given page or not related utility files
-
Get all resolution paths for a suspicious file
rev-dep resolve path/to/suspicious-file path/to/entry-point --all
-
You would usually find out that there is some file, like directory index
file that given entry point is using, which is mandatory, but as a side effect it imports a few files that are redundant for your entry point. In most cases you should be able to decouple the imports or reverse the dependency to cut off the resolution path for the unwanted file
Usage 🎨
Project can be used as a CLI tool or as a module
CLI Tool
For CLI usage see CLI reference
Module
resolve
Function
import { resolve } from "rev-dep";
const [paths] = await resolve({
entryPoints: ["index.js"],
filePath: "utils.js",
});
console.log(paths);
getEntryPoints
Function
import { getEntryPoints } from "rev-dep";
const [entryPoints] = await getEntryPoints({
cwd: process.cwd(),
});
console.log(entryPoints);
CLI reference 📖
Command resolve
Checks if a filePath is required from entryPoint(s) and prints the resolution path
Usage
rev-dep resolve <filePathOrNodeModuleName> [entryPoints...] [options]
Arguments
filePathOrNodeModuleName
- undefined (required)entryPoints...
- List of entry points to look for file (optional)
Options
-wc, --webpackConfig <path>
- path to webpack config to enable webpack aliases support (optional)--cwd <path>
- path to a directory that should be used as a resolution root (optional)-i --include <globs...>
- A list of globs to determine files included in entry points search (optional)-e --exclude <globs...>
- A list of globs to determine files excluded in entry points search (optional)-cs, --compactSummary
- print a compact summary of reverse resolution with a count of found paths (optional)-a, --all
- finds all paths combination of a given dependency. Might work very slow or crash for some projects due to heavy usage of RAM (optional)-ntp --notTraversePaths <paths...>
- Specify file paths relative to resolution root, that should not be traversed when finding dependency path (optional)-inm --includeNodeModules
- Whether to include node modules in dependency graph. Has to be provided to resolve node module. (optional)-iti --ignoreTypesImports
- Use this flag to not follow type imports when resolving modules (optional)
Command entry-points
Print list of entry points in current directory
Usage
rev-dep entry-points [options]
Options
-wc, --webpackConfig <path>
- path to webpack config to enable webpack aliases support (optional)--cwd <path>
- path to a directory that should be used as a resolution root (optional)-i --include <globs...>
- A list of globs to determine files included in entry points search (optional)-e --exclude <globs...>
- A list of globs to determine files excluded in entry points search (optional)-pdc, --printDependenciesCount
- print count of entry point dependencies (optional)-c, --count
- print just count of found entry points (optional)-iti --ignoreTypesImports
- Use this flag to not follow type imports when resolving modules (optional)
Command files
Get list of files required by entry point
Usage
rev-dep files <entryPoint> [options]
Arguments
entryPoint
- Path to entry point (required)
Options
-wc, --webpackConfig <path>
- path to webpack config to enable webpack aliases support (optional)--cwd <path>
- path to a directory that should be used as a resolution root (optional)-c, --count
- print only count of entry point dependencies (optional)-iti --ignoreTypesImports
- Use this flag to not follow type imports when resolving modules (optional)
Command node-modules
Get list of node modules required by entry point
Usage
rev-dep node-modules <entryPoint> [options]
Arguments
entryPoint
- Path to entry point (required)
Options
-wc, --webpackConfig <path>
- path to webpack config to enable webpack aliases support (optional)--cwd <path>
- path to a directory that should be used as a resolution root (optional)-c, --count
- print only count of entry point dependencies (optional)-iti --ignoreTypesImports
- Use this flag to not follow type imports when resolving modules (optional)
Command docs
Generate documentation of available commands into md file.
Usage
rev-dep docs <outputPath> [options]
Arguments
outputPath
- path to output *.md file (required)
Options
-hl, --headerLevel <value>
- Initial header level (optional)
Export from problem
rev-dep
attempts to also solve export * from
by a babel plugin that can be used as follows
module.exports = {
plugins: ["rev-dep/babel"],
};
The plugins is currently experimental and might not work for all codebases!
It helps by rewiring paths to re-exported modules
import { add } from "./utils";
export * from "./math";
export * from "./otherModule";
export * from "./anotherModule";
export const add = () => {};
And for file.ts
it would rewire the import like this
import { add } from "./utils/math";
So as a result, we don't implicitly require ./otherModule
and ./anotherModule
which we will not use anyway
Benefits
I don't have solid evidence for this, but I think it reduced RAM usage of the dev server I worked with (blitz.js). It crashed less often due to reaching heap size limit.
But for sure it reduced bundle size, slightly, but still 😀
It all depends on the the project dependencies structure.
By using the babel plugin you will reduce a risk of problems like implicitly importing front-end
modules on the server
or similar while still being able to benefit from short import paths.
Once I got an incident that, after a rebase with main branch, my project stopped compiling due to the problem caused by export * from
. I spend a few hours debugging that, very frustrating.
Contributing
Project is open to contributions, just rise an issue if you have some ideas about features or you noticed a bug. After discussion we can approach implementation :)
Development
- Clone repo
- Install deps using
yarn
- Run
yarn build:watch
- Code!
For testing purpose use
yarn dev [command] --cwd path/to/some/codebase
or you can install CLI tool from the file system using
yarn global add $PWD
and then just run
rev-dep
Made with 🧠 by @jayu
I hope that this small piece of software will help you discover and understood complexity of your project hence make you more confident while refactoring. If this tool was useful, don't hesitate to give it a ⭐!