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