Find unused npm packages in package json

Question

Is there a way to determine if you have packages in your package json file that are no longer needed    For instance  when trying out a package and later commenting or deleting code  but forgetting to uninstall it  I end up with a couple packages that could be deleted    What would be an efficient way to determine if a package could safely be deleted

User · Answer

many of the answer here are how to find unused items.

I wanted to remove them automatically.

Install this node project.

$ npm install -g typescript tslint tslint-etc

At the root dir, add a new file tslint-imports.json

{ "extends": [ "tslint-etc" ], "rules": { "no-unused-declaration": true } }

Run this at your own risk, make a backup :)

$ tslint --config tslint-imports.json --fix --project .

User · Answer

fiskeben wrote      The downside is that it s not fully automatic  i e  it doesn t extract package names from package json and check them  You need to do this for each package yourself    Let s make Fiskeben s answer automated if for whatever reason depcheck is not working properly   E g  I tried it with Typescript and it gave unnecessary parsing errors   For parsing package json we can use the software jq  The below shell script requires a directory name where to start      bin bash DIRNAME   1 -   cd  DIRNAME  FILES   mktemp  PACKAGES   mktemp   find         -path   node modules -prune -or       -path   build -prune -or          -name    ts  -or -name    js  -or -name    json     -print  gt   FILES  function check       cat package json             jq         1   keys              sed -n  s               1 p   gt   PACKAGES      echo  --------------------------      echo  Checking  1         while read PACKAGE     do         RES   cat  FILES   xargs -I    egrep -i   import require         PACKAGE              wc -l          if    RES   0           then             echo -e  UNUSED t t  PACKAGE          else             echo -e  USED   RES  t  PACKAGE          fi     done  lt   PACKAGES    check  dependencies  check  devDependencies  check  peerDependencies    First it creates two temporary files where we can cache package names and files   It starts with the find command  The first and second line make it ignore the node modules and build folders  or whatever you want   The third line contains allowed extensions  you can add more here e g  JSX or JSON files   A function will read dependendy types   First it cats the package json  Then  jq gets the required dependency group        is there so that it won t throw an error if e g  there are no peer dependencies in the file     After that  sed extracts the parts between the quotes  the package name  -n and     p tells it to print the matching parts and nothing else from jq s JSON output  Then we read this list of package names into a while loop   RES is the number of occurrences of the package name in quotes  Right now it s import require      package   package   It does the job for most cases   Then we simply count the number of result lines then print the result   Caveats    Won t find files in different imports e g  tsconfig json files  lib option  You have to grep manually for only  USED and UNUSED files  It s slow for large projects - shell scripts often don t scale well  But hopefully you won t be running this many times

User · Answer

We can use the below npm module for this purpose   https   www npmjs com package npm-check-unused

User · Answer

If you re using a Unix like OS  Linux  OSX  etc  then you can use a combination of find and egrep to search for require statements containing your package name   find   -path   node modules -prune -o -name    js  -exec egrep -ni  name-of-package          If you search for the entire require  name-of-package   statement  remember to use the correct type of quotation marks   find   -path   node modules -prune -o -name    js  -exec egrep -ni  require  name-of-package            or  find   -path   node modules -prune -o -name    js  -exec egrep -ni  require  name-of-package            The downside is that it s not fully automatic  i e  it doesn t extract package names from package json and check them  You need to do this for each package yourself  Since package json is just JSON this could be remedied by writing a small script that uses child process exec to run this command for each dependency  And make it a module  And add it to the NPM repo

User · Answer

There is also a package called npm-check      npm-check      Check for outdated  incorrect  and unused dependencies      It is quite powerful and actively developed  One of it s features it checking for unused dependencies - for this part it uses the depcheck module mentioned in the other answer

User · Answer

You can use an npm module called depcheck  requires at least version 10 of Node    Install the module   npm install depcheck -g   or   yarn global add depcheck   Run it and find the unused dependencies   depcheck    The good thing about this approach is that you don t have to remember the find or grep command  To run without installing use npx  npx depcheck

User · Answer

The script from gombosg is much better then npm-check  I have modified a little bit  so devdependencies in node modules will also be found  example sass never used  but needed in sass-loader    bin bash DIRNAME   1 -   cd  DIRNAME  FILES   mktemp  PACKAGES   mktemp     use fd   https   github com sharkdp fd  function check       cat package json             jq  quot        1   keys quot              sed -n  s    quot        quot     1 p   gt   PACKAGES     echo  quot -------------------------- quot      echo  quot Checking  1    quot      fd   js ts json    -t f  gt   FILES     while read PACKAGE     do         if   -d  quot node modules   PACKAGE  quot     then             fd  -t f   js ts json    node modules   PACKAGE   gt  gt   FILES         fi         RES   cat  FILES   xargs -I    egrep -i  quot  import require loader plugins   PACKAGE        quot     PACKAGE     d     quot    quot         wc -l           if    RES   0           then             echo -e  quot UNUSED t t  PACKAGE quot          else             echo -e  quot USED   RES  t  PACKAGE quot          fi     done  lt   PACKAGES    check  quot dependencies quot  check  quot devDependencies quot  check  quot peerDependencies quot   Result with original script  -------------------------- Checking dependencies    UNUSED           jquery -------------------------- Checking devDependencies    UNUSED            types jquery UNUSED            types jqueryui USED  1          autoprefixer USED  1          awesome-typescript-loader USED  1          cache-loader USED  1          css-loader USED  1          d3 USED  1          mini-css-extract-plugin USED  1          postcss-loader UNUSED           sass USED  1          sass-loader USED  1          terser-webpack-plugin UNUSED           typescript UNUSED           webpack UNUSED           webpack-cli USED  1          webpack-fix-style-only-entries  and the modified  Checking dependencies    USED  5          jquery -------------------------- Checking devDependencies    UNUSED            types jquery UNUSED            types jqueryui USED  1          autoprefixer USED  1          awesome-typescript-loader USED  1          cache-loader USED  1          css-loader USED  2          d3 USED  1          mini-css-extract-plugin USED  1          postcss-loader USED  3          sass USED  1          sass-loader USED  1          terser-webpack-plugin USED  16         typescript USED  16         webpack USED  2          webpack-cli USED  2          webpack-fix-style-only-entries

User · Answer

As other answer mentioned depcheck is good for check unused dependecies in your porject  Use npm outdated command to check the outdated library

User · Answer

if you want to choose upon which giant s shoulders you will stand here is a link to generate a short list of options available to npm  it filters on the keywords unused packages https   www npmjs com search q unused 20packages

[node.js] Find unused npm packages in package.json

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