Find unused npm packages in package.json
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
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Check for outdated, incorrect, and unused dependencies.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.
Check the unused dependencies
npm install depcheck -g
depcheck
Check the outdated library
npm outdated
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 > $FILES
function check {
cat package.json \
| jq "{} + .$1 | keys" \
| sed -n 's/.*"\(.*\)".*/\1/p' > $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 < $PACKAGES
}
check "dependencies"
check "devDependencies"
check "peerDependencies"
First it creates two temporary files where we can cache package names and files.
It starts with the find
command. The first and second line make it ignore the node_modules
and build
folders (or whatever you want). The third line contains allowed extensions, you can add more here e.g. JSX or JSON files.
A function will read dependendy types.
First it cat
s the package.json
. Then, jq
gets the required dependency group. ({} +
is there so that it won't throw an error if e.g. there are no peer dependencies in the file.)
After that, sed
extracts the parts between the quotes, the package name. -n
and .../p
tells it to print the matching parts and nothing else from jq
's JSON output. Then we read this list of package names into a while
loop.
RES
is the number of occurrences of the package name in quotes. Right now it's import
/require
... 'package'
/"package"
. It does the job for most cases.
Then we simply count the number of result lines then print the result.
Caveats:
- Won't find files in different imports e.g.
tsconfig.json
files (lib
option) - You have to
grep
manually for only^USED
andUNUSED
files. - It's slow for large projects - shell scripts often don't scale well. But hopefully you won't be running this many times.
The script from gombosg is much better then npm-check.
I have modified a little bit, so devdependencies in node_modules will also be found.
example sass
never used, but needed in sass-loader
#!/bin/bash
DIRNAME=${1:-.}
cd $DIRNAME
FILES=$(mktemp)
PACKAGES=$(mktemp)
# use fd
# https://github.com/sharkdp/fd
function check {
cat package.json \
| jq "{} + .$1 | keys" \
| sed -n 's/.*"\(.*\)".*/\1/p' > $PACKAGES
echo "--------------------------"
echo "Checking $1..."
fd '(js|ts|json)$' -t f > $FILES
while read PACKAGE
do
if [ -d "node_modules/${PACKAGE}" ]; then
fd -t f '(js|ts|json)$' node_modules/${PACKAGE} >> $FILES
fi
RES=$(cat $FILES | xargs -I {} egrep -i "(import|require|loader|plugins|${PACKAGE}).*['\"](${PACKAGE}|.?\d+)[\"']" '{}' | wc -l)
if [ $RES = 0 ]
then
echo -e "UNUSED\t\t $PACKAGE"
else
echo -e "USED ($RES)\t $PACKAGE"
fi
done < $PACKAGES
}
check "dependencies"
check "devDependencies"
check "peerDependencies"
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