Registry / serialization / node-red-contrib-json

node-red-contrib-json

library0.2.0jsnpmunverified

A Node-RED node for processing JSON objects using multiple query engines: JSONSelect, JSONPath, jq, and json-select. Current stable version is 0.2.0. Release cadence is irregular; this package is in early maintenance mode. Key differentiators include support for multiple query languages in one node and the ability to choose between lightweight (JSONSelect) and powerful (jq) engines. The jq engine requires the jq command-line tool to be installed separately, which is a notable dependency compared to pure JavaScript alternatives. The node integrates into Node-RED's flow-based programming environment, allowing visual wiring of JSON transformations.

serialization data http-networking

npm install node-red-contrib-json

github ↗package ↗

INSTALL

IMPORT

SIG · NODE-RED-CONTRIB-J

node-red-contrib-json

serializationjavascriptv0.2.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

contrib-json

✓ Node-red node, installed via npm package 'node-red-contrib-json'. No JavaScript import needed; add node from Node-RED palette.

✗ require('node-red-contrib-json')

This is a Node-RED contrib node, not a library. It is used by adding the 'contrib-json' node from the Node-RED palette after installation.

Shows installation, configuration, and usage of the contrib-json node with JSONSelect engine.

Install the package in your Node-RED user directory: npm install node-red-contrib-json Then restart Node-RED and add a 'contrib-json' node from the palette. Configure it by selecting an engine (e.g., JSONSelect) and an expression (e.g., '.foo'). Wire input and output nodes. Deploy and send a message with msg.payload = {"foo": "bar"}. The output msg.payload will contain ["bar"] as an array.

Debug

Known issues

gotchajq engine requires the jq command-line tool to be installed separately; if not found, the node may fail silently or produce no output.

fix

Install jq from https://stedolan.github.io/jq/ and ensure it is in your system PATH.

affects: >=0.1.0

gotchaThe JSONSelect engine uses recursive descent by default (like CSS), which may produce unexpected results if you are not familiar with the syntax.

fix

Use the '>' combinator for direct children, e.g., '.foo > .bar' instead of '.foo .bar'.

affects: >=0.1.0

gotchaOutput format varies by engine: JSONSelect and JSONPath return arrays; jq returns one message per result (possibly multiple messages); json-select returns the result directly (may be array).

fix

Check the engine documentation and handle output accordingly; use a Node-RED function node to convert if needed.

affects: >=0.1.0

gotchaThe node modifies msg.payload only; other properties of the message are passed through unchanged.

fix

If you need to preserve original payload, store it in another property before this node.

affects: >=0.1.0

Errors

Common errors & fixes

Error: Cannot find module 'node-red-contrib-json'

Node-RED cannot find the installed package, or the package was installed in the wrong directory.

fix

Install the package in your Node-RED user directory (usually ~/.node-red): cd ~/.node-red && npm install node-red-contrib-json

Input payload must be a valid JSON object

The node expects msg.payload to be a JSON object, but receives a string or other type.

fix

Use a JSON parse node before this node to convert strings to objects.

jq: command not found

The jq command-line tool is not installed or not in PATH.

fix

Install jq from https://stedolan.github.io/jq/ and ensure it is available in the system PATH.

Upgrade

Version history

0.2.0latest on npm

Audit

Dependencies

jqoptionalFor the jq engine to work, the jq command-line tool must be installed and available in the system PATH.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/jimbojw/node-red-contrib-json ↗

packagehttps://www.npmjs.com/package/node-red-contrib-json ↗