Small implementation of jq

Usage no npm install needed!

<script type="module">
  import elasticMicroJq from 'https://cdn.skypack.dev/@elastic/micro-jq';



A small implementation of JQ.

What is it?

jq is a fantastic tool for wrangling JSON, but it's written in C and so cannot be used in a browser. This project implements a subset of the JQ filter language, and is intended for simple filtering jobs in JavaScript where the filter is supplied e.g. by a user.

How does it work?

It uses a parsed expression grammar (via Peggy) to transform JQ expressions into a series of "op codes", with each one representing a JQ filter operation. Each op code is executed with a context, which is initialised with the input object. As each op code executes, the context is updated.


  • Implement enough of the JQ syntax to be useful
  • Implement it the same as JQ


  • Complete implementation of JQ (but the level of completeness may increase over time).