jt — Swiss Army Knife for JSON

A zero-dependency CLI tool for working with JSON. Format, minify, query, diff, validate, flatten, convert to CSV, and more.

Install

npm install -g jt-cli

Or run directly with npx:

npx jt-cli fmt data.json

Usage

# Format / pretty-print
cat data.json | jt fmt
jt format data.json -c        # with colors

# Minify
jt min data.json

# Query with dot notation
jt query users.0.name data.json
echo '{"a":{"b":42}}' | jt q a.b

# List keys / values
jt keys data.json
jt values data.json

# Flatten nested JSON
echo '{"user":{"name":"Adam","addr":{"city":"Rabat"}}}' | jt flatten
# → {"user.name":"Adam","user.addr.city":"Rabat"}

# Diff two JSON files
jt diff before.json after.json
# + $.newKey: "added"
# - $.removed: "gone"
# ~ $.changed: "old" → "new"

# Validate
jt validate data.json
echo '{bad json' | jt validate

# Convert to CSV
jt csv users.json > users.csv
jt tsv users.json > users.tsv

# Sort keys
jt sort messy.json

# Pick / omit keys
echo '{"a":1,"b":2,"c":3}' | jt pick a,c
echo '{"a":1,"secret":"x"}' | jt omit secret

# NDJSON
jt ndjson array.json           # array → newline-delimited
jt fromlines stream.ndjson     # newline-delimited → array

# Stats
jt stats large.json
# Size: 1.2 MB
# Type: array
# Depth: 4
# Total keys: 15000
# ...

Why jt?

• Zero dependencies — just Node.js
• Pipes well — reads stdin, writes stdout
• Fast — no startup overhead
• Familiar — if you know jq, you'll feel at home
• 20+ commands — covers common JSON operations

Commands

Command	Description
fmt	Pretty-print with indentation
min	Minify (remove whitespace)
query <path>	Query with dot notation
keys	List top-level keys
values	List top-level values
type	Show JSON value type
count	Count items/keys
flatten	Flatten nested to dot paths
unflatten	Reverse flatten
diff <a> <b>	Diff two JSON files
validate	Check if valid JSON
csv	Convert array to CSV
tsv	Convert array to TSV
sort	Sort keys recursively
pick <keys>	Keep only listed keys
omit <keys>	Remove listed keys
ndjson	Array to newline-delimited
fromlines	NDJSON to array
stats	Show depth, types, counts

License

MIT