jaycue is my little side project that mimics the best parts jq in pure JavaScript. I wrote a blog post about it on dev.to

I am TDD'ing this to get some practice, using the jq documentation, and hopefully make something useful. Please see below for some similar, more mature, great projects built around jq.

Install

$ npm install jaycue

Usage

const jq = require('jaycue');

console.log(jq({foo: 123}, '.foo'));
123

Supported Filters

Basic Filters

{
  "value": 42,
  "text": "less interesting data",
  "name": {
    "first": "Brian"
    "last": "Olore"
  }
}

filter	output
.	{ "value": 42, "text": "less interesting data","name": { "first": "Brian" "last": "Olore" } } (object)
.value	42 (number)
.text	less interesting data (string)
.["text"]	less interesting data (string)
.name	"name": { "first": "Brian" "last": "Olore" } (object)
.name.first	Brian (string)
.missing	undefined
.missing?	null
.["missing"]?	null

Array Filters

["a","b","c","d","e"];

filter	output
.[]	"a","b","c","d","e" (not json)
.[0]	a
.[-2]	d

Array Slicing Filters

filter	output
.[2:4]	["c", "d"]
.[:3]	["a", "b", "c"]
.[:-3]	["a", "b"]
.[-2:]	["d", "e"]
.[2:]	["c", "d", "e"]

Select Function

[
  {"id": "first", "val": 1},
  {"id": "second", "val": 2}
]

filter	output
.[] | select(.id == "second")	{"id": "second", "val": 2}
.[] | select(.id == "second") | .val	2 (number)
.[] | select(.id == "second") .val	2 (number)
.[] | select(.id != "second") .val	1 (number)

Testing

Must have jq installed to run tests jq is now supplied by node-jq

As previously mentioned, all code has been test-driven. The test-helper provides a way to call the actual jq, making it easy to compare results.

Running tests

npm test

Notes

Read the jq Language Description

Check out this project which is a JavaScript wrapper around jq: https://github.com/sanack/node-jq. Here are some more cool jq projects: https://github.com/fiatjaf/awesome-jq

Thanks

• Logo by Joseph Olore