Only run prettier if a config file is present

prettier.sh

#!/bin/bash

# find the file prettier is trying to prettify
file=${BASH_ARGV[0]:="."}

# optionally set where the real prettier command can be found
prettier=`which prettier`

# try to see if there is a project-specific `prettier` to use
node_modules=`npm root`
if [ -f "${node_modules}/.bin/prettier" ]; then
   prettier="$node_modules/.bin/prettier"
fi

if $prettier --find-config-path ${file} > /dev/null; then
    exec $prettier "$@"
else
    exec cat <&0
fi