jaq – clone of the JSON data processing tool

jaq is a jq clone focused on correctness, speed, and simplicity.

It aims to support a large subset of jq’s syntax and operations.

This is free and open source software.

Key Features

• Basics:
  • Identity (.)
  • Recursion (..)
  • Basic data types (null, boolean, number, string, array, object)
  • if-then-else (if .a < .b then .a else .b end)
  • Folding (reduce .[] as $x (0; . + $x), foreach .[] as $x (0; . + $x; . + .))
  • Error handling (try … catch …)
  • String interpolation (“The successor of \(.) is \(.+1).”)
  • Format strings (@json, @text, @csv, @tsv, @html, @sh, @base64, @base64d)
• Paths:
  • Indexing of arrays/objects (.[0], .a, .[“a”])
  • Iterating over arrays/objects (.[])
  • Optional indexing/iteration (.a?, .[]?)
  • Array slices (.[3:7], .[0:-1])
  • String slices
• Operators:
  • Composition (|)
  • Binding (. as $x | $x)
  • Concatenation (,)
  • Plain assignment (=)
  • Update assignment (|=, +=, -=)
  • Alternation (//)
  • Logic (or, and)
  • Equality and comparison (.a == .b, .a < .b)
  • Arithmetic (+, -, *, /, %)
  • Negation (-)
  • Error suppression (?)
• Definitions:
  • Basic definitions (def map(f): [.[] | f];)
  • Recursive definitions (def r: r; r)
• Core filters:
  • Empty (empty)
  • Errors (error)
  • Input (inputs)
  • Length (length, utf8bytelength)
  • Rounding (floor, round, ceil)
  • String <-> JSON (fromjson, tojson)
  • String <-> integers (explode, implode)
  • String normalisation (ascii_downcase, ascii_upcase)
  • String prefix/postfix (startswith, endswith, ltrimstr, rtrimstr)
  • String splitting (split(“foo”))
  • Array filters (reverse, sort, sort_by(-.), group_by, min_by, max_by)
  • Stream consumers (first, last, range, fold)
  • Stream generators (range, recurse)
  • Time (now, fromdateiso8601, todateiso8601)
  • More numeric filters (sqrt, sin, log, pow, …) (list of numeric filters)
• Standard filters:
  • These filters are defined via more basic filters. Their definitions are at std.jq.
  • Undefined (null)
  • Booleans (true, false, not)
  • Special numbers (nan, infinite, isnan, isinfinite, isfinite, isnormal)
  • Type (type)
  • Filtering (select(. >= 0))
  • Selection (values, nulls, booleans, numbers, strings, arrays, objects, iterables, scalars)
  • Conversion (tostring, tonumber)
  • Iterable filters (map(.+1), map_values(.+1), add, join(“a”))
  • Array filters (transpose, first, last, nth(10), flatten, min, max)
  • Object-array conversion (to_entries, from_entries, with_entries)
  • Universal/existential (all, any)
  • Recursion (walk)
  • I/O (input)
  • Regular expressions (test, scan, match, capture, splits, sub, gsub)
  • Time (fromdate, todate)
• Numeric filters – imports many filters from libm and follows their type signature.

Website: github.com/01mf02/jaq
Support:
Developer: Michael Färber
License: MIT License

jaq is written in Rust. Learn Rust with our recommended free books and free tutorials

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