https://github.com/mwh/jqjs
Pure-JavaScript implementation of the jq JSON query language
https://github.com/mwh/jqjs
jq
Last synced: 5 months ago
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Pure-JavaScript implementation of the jq JSON query language
- Host: GitHub
- URL: https://github.com/mwh/jqjs
- Owner: mwh
- License: mit
- Created: 2018-10-19T00:14:58.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2024-11-16T19:43:23.000Z (11 months ago)
- Last Synced: 2025-04-11T18:25:01.735Z (6 months ago)
- Topics: jq
- Language: JavaScript
- Size: 114 KB
- Stars: 87
- Watchers: 3
- Forks: 7
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
- Citation: CITATION.cff
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README
jqjs is a JavaScript implementation of the [jq] query language. It
implements the core language features in pure JavaScript.
The main entry point to jqjs is the compile function, which turns a jq
program string into a generator function:
import jq from './jq.js'
let filter = jq.compile(".x[].y")
for (let v of filter({x:[{y:2}, {y:4}]}) { ... }
The module also has a prettyPrint function for rendering an object to
text.
Features
--------
jqjs supports *most* of the core jq language features, but lacks
functions and some of the advanced functionality. It also uses
JavaScript strings as backing, so does not have jq proper's Unicode
support.
- [x] Identity: `.`
- [x] Object Identifier-Index: `.foo`, `.foo.bar`
- [x] Generic Object Index: `.[]`
- [x] Array Index: `.[2]`
- [x] Array/String Slice: `.[10:15]`
- [x] Array/Object Value Iterator: `.[]`
- [x] Comma: `,`
- [x] Pipe: `|`
- [x] Parentheses: `(...)`
- [x] Array Construction: `[...]`
- [x] Object Construction: `{ ... }` including shorthand `{ user, title }`
and computed keys `{ (.x): true }`
- [x] Recursive Descent: `..`
- [x] Addition, subtraction, multiplication, division, and modulo,
including the overloaded type operations.
- [x] Named functions
- Built-in functions
- [x] tostring, tonumber, path, length, keys, has, in, type, del
- [x] empty, select, arrays, objects, booleans, numbers, strings, nulls
- [x] map, map_values, add, sort, sort_by, explode, implode, split, join
- [x] to_entries, from_entries, with_entries
- [x] range/1, range/2, range/3
- [x] any/0, any/1, any/2, all/0, all/1, all/2
- [x] contains, inside
- [ ] the others
- [ ] User-defined functions
- [ ] Mathematical functions
- [x] String interpolation: `\(foo)`
- [x] Format strings and escaping: `@text`, `@json`, `@html`, `@uri`, `@csv`,
`@tsv`, `@sh`, `@base64`, `@base64d`
- [x] Format interpolations: `@uri "https://google.com/search?q=\(.x)"`
- [x] Equality checks: `==`, `!=`
- [x] Comparisons: `<`, `>`, `<=`, `>=`
- [x] Correct sorting order for unequal types (`null < 7`, `[] < {}`)
- [x] Conditionals: `if A then B elif C then D else E end`
- [x] Alternative operator: `//`
- [ ] Try-catch: `try EXP catch EXP`
- [x] Error Suppression operator `?`
- [ ] Regular expressions
- [x] Variable/Symbolic Binding Operator `... as $identifier | ...`
- [x] Reduce: `reduce .[] as $item (0; . + $item)`
- [ ] foreach: `foreach .[] as $item (...;...;...)`
- [ ] Recursion: `recurse(.children[])`
- [ ] I/O (unlikely to make sense here)
- [x] Update-assignment: `.posts[].comments |= . + ["Another"]`
- [x] Arithmetic update-assignment: `+=`, `-=`, `*=`, `/=`, `%=`, `//=`
- [ ] Plain assignment: `(.a,.b) = range(2)`
- [ ] Modules with `import` and `include`
Performance
-----------
Not great.
The intention is to be semantically correct first and to have clear code
second. Performance improvements sit after that, if at all. Executing a
program may reëvaluate parts of it or traverse the object multiple times
where that makes things simpler, and internally evaluation happens by
tree-walking the input syntax.
Demonstration
-------------
[demo.html] is a [live demo](https://mwh.github.io/jqjs/demo.html) of how
to use jqjs that lets you enter a jq program and an input JSON value and
see the output JSON values it produces.
[jq]: https://stedolan.github.io/jq/
[demo.html]: demo.html