json-fingerprint

Fingerprint JSON by calculating the hash (default: sha256) based on the shape of the JSON and its value types.

Install

1npm install json-fingerprint

Usage

1import {fingerprintJSON} from 'json-fingerprint';

1const {hash, jsonPaths} = fingerprintJSON(`{"foo":"bar"}`)
2// hash = 3e61d854042bcd6273a8e18589eb53a37e4cdc111bd2dc717413951637c11e2d
3// jsonPaths = ['$:object', '$.foo:string']
4
5const {hash, jsonPaths} = fingerprintJSON(`{"foo":"some string"}`)
6// hash = 3e61d854042bcd6273a8e18589eb53a37e4cdc111bd2dc717413951637c11e2d
7// jsonPaths = ['$:object', '$.foo:string']

Options

1// JSON input
2fingerprintJSON(`{"foo":"bar"}`)
3
4// object input
5fingerprintJSON({"foo":"bar"})
6
7// custom hash function
8fingerprintJSON(`{"foo":"bar"}`, myCustomHashFn)

Result

1const {hash, jsonPaths, source} = fingerprintJSON(`{"foo":"bar"}`)

• hash: fingerprint hash of the JSON
• jsonPaths: internal JSON meta data (hash is calculated based on stringified jsonPaths)
• source: original JSON provided as input

Custom hash function

1import { createHash } from 'node:crypto';
2
3function sha512(data) {
4  /**
5   * https://nodejs.org/api/crypto.html#cryptocreatehashalgorithm-options
6   * `openssl list -digest-algorithms` to display the available digest algorithms
7   */
8  return createHash('sha512').update(data).digest('hex');
9}
10
11fingerprintJSON(`{"foo":"bar"}`, sha512);

CLI

hash a JSON file

1npx json-fingerprint --file=package.json
2$ c0f87b9c30f33f44e9723c192d1797c161fb53e22ce06615cb6738d2bfb7b25d

pipe to json-fingerprint

1cat package.json | npx json-fingerprint
2$ c0f87b9c30f33f44e9723c192d1797c161fb53e22ce06615cb6738d2bfb7b25d

1wget -qO - https://github.com/chimurai/json-fingerprint/raw/main/package.json | npx json-fingerprint
2$ c0f87b9c30f33f44e9723c192d1797c161fb53e22ce06615cb6738d2bfb7b25d