jq json tree traversal (npm node_modules) - npm

Question

The question concerns the code optimization.
I want to define a json-file which specify what files will be copied and where. Namely, I want to apply it in npm-type project to transfer the files from node_modules to the destination directory from which I include files (on the templates of the pages for the web browser). So I wrote a json file:
{
"public": [
{
"bootstrap": {
"js": [
"bootstrap.min.js"
],
"css": [
"bootstrap.min.css"
]
}
},
{
"jquery": {
"js": [
"jquery.min.js"
]
}
}
]
}
The first level defines the name of the destination directory ('public') which would contain the packages specified on the second level. The third level defines the names of the destination folders inside 'public' ('js' or 'css') which contain the list of files to find and copy.
The code which traverses the json file follows:
#!/usr/bin/env bash
cfg='push2public.json'
P=$(cat "$cfg" | jq keys[0] -r)
n=$(cat "$cfg" | jq ".$P | length")
for (( i=0;i<$n;i++ )); do
p=$(cat "$cfg" | jq ".$P[$i]" | jq keys[0] -r)
m=$(cat "$cfg" | jq ".$P[$i].$p | length")
for (( j=0;j<$m;j++ )); do
d=$(cat "$cfg" | jq ".$P[$i].$p" | jq keys[$j] -r)
mkdir -p "$P/$d"
l=$(cat "$cfg" | jq ".$P[$i].$p" | jq ".$d | length" )
for (( k=0;k<$l;k++ )); do
f=$(cat "$cfg" | jq ".$P[$i].$p.$d[$k]" -r)
find . -path "./node_modules/$p/*" -name "$f" | xargs -I{} cp -fa "{}" "$P/$d/"
done
done
done
The code seems to work, yet it looks kinda strange. Can you think of a better way to apply jq for the task just described?

Answer 1

In this response, I'll focus on the main point - that it is possible to construct the
shell commands with just one invocation of jq. jq does not have a "system" command
for executing these commands, so the jq program given here may need to be modified, depending e.g. on security requirements.
To get the ball rolling, note that the script given in the question generates (and executes)
the following shell commands:
find . -path ./node_modules/bootstrap/* -name bootstrap.min.css | xargs -I{} cp -fa {} public/css/
find . -path ./node_modules/bootstrap/* -name bootstrap.min.js | xargs -I{} cp -fa {} public/js/
find . -path ./node_modules/jquery/* -name jquery.min.js | xargs -I{} cp -fa {} public/js/
These commands can be generated with just one invocation of jq using the following jq program:
def construct:
(.value | to_entries[] | "-name \(.value[0]) | xargs -I{} cp -fs {} public/\(.key)/") as $s
| "find . -path ./node_modules/\(.key)/* " + $s ;
.[][]
| to_entries[]
| construct
Note that in the output produced by this jq program, the ordering is different, because the script in the question uses keys, which sorts the keys alphabetically.