FP Json CLI

fq is a command line tool that embodies the Unix philosophy of small, composable functions that can be piped together using the | operator. It simplifies the process of filtering and querying JSON data, drawing inspiration from popular tools like jq et al., while aiming to provide a more familiar experience for JavaScript and Typescript developers.

Table of Contents

• Installation
• Usage
  • Examples
    • List all Operators in Reverse Order
    • Remove Properties from API Data
  • CLI
  • Operators
• TODO

Installation

npm install --global fp-json-cli

yarn global add fp-json-cli

pnpm install --global fp-json-cli

Usage

You can either read JSON data from stdin by using a command like cat package.json | fq ".name", or provide the file name as the second argument, eg. fq ".name" package.json.

One of the more interesting use cases for fq is when you want to change the format of JSON data. By piping together multiple fq operators, you can transform JSON data from one format to another easily.

Examples

List all Operators in Reverse Order

fq list --json | fq "chain(.alias) | sort(.) | reverse(.)"

• fq list --json: Write all available operators in JSON format to stdout.
• chain(.alias): Is a shorthand for flatMap(get(alias)), which concatenates the alias JSON arrays together.
• sort(.): Sort the JSON array.
• reverse(.): Reverse the sorted array.

Remove Properties from API Data

curl -X GET https://jsonplaceholder.typicode.com/users > users.json # save response to a file
fq -o users-out.json "map(u(omit(company), p(address, .address|omit(geo)))) | filter(.id >= 4) | take(2)" users.json

• map(u(omit(company), p(address, .address|omit(geo)))): This operation maps each user object in the JSON data. It omits the company field from the user object and re-projects the address field without the geo field.
• filter(.id >= 4): Filters the mapped user objects based on the condition that the id field is greater than or equal to 4.
• take(2): Takes the first 2 filtered user objects.

The final result of these operations is written to the users-out.json file.

CLI

fq/0.1.0

Usage:
  $ fq <query> [file]

Commands:
  <query> [file]  Run fp style operators on input file or stdin
  list            List available operators

For more info, run any command with the `--help` flag:
  $ fq --help
  $ fq list --help

Options:
  -o, --out <path>  Write the result to a file 
  --no-nl           Control new line at the end output (default: true)
  --show-ast        Dump AST to stdout 
  --show-ir         Dump intermediate representation to stdout 
  -h, --help        Display this message 
  -v, --version     Display version number 

Examples:
fq "map(union(pick(email, name), project(age, meta.age)) | filter(.age > 2)" users.json

Operators

Name	Alias
add
constant	c
count	len
divide	div
entries
equals	eq
every	and
filter
flatMap	chain
flow
get	pluck
greaterThan	gt
greaterThanEquals	gte
identity	id, i
includes	has
lessThan	lt
lessThanEquals	lte
map
multiply	mul
not
notEquals	neq
omit
pick
project	p
range
reverse
skip
some	or
sort
subract	sub
take
union	u
unique	uniq

TODO

• [ ] Error reporting
• [ ] Type checking
• [ ] Reduce/fold operator
• [ ] Streaming parsing and serializing for large files
• [ ] Highlight output similar to jq