A complete implementation of JSON Pointer (RFC 6901) for nodejs and modern browsers.
Supports Relative JSON Pointers. (Example)
I wrote this a few years back when I was unable to find a complete implementation of RFC 6901. It turns out that I now use the hell out of it. I hope you also find it useful.
npm install json-ptr
As of v3.0.0, we provide CJS, ESM, and UMD builds under the dist/
folder when you install the package from NPM, we also have all appropriate references in our package.json
file, so your code should just work. If you need a CDN reference for a website or the like, try UNPKG, which picks up our releases automatically.
CDN: https://unpkg.com/browse/json-ptr@3.0.2/dist/json-ptr.min.js.
Both CJS and ESM are supported.
const { JsonPointer } = require('json-ptr');
import { JsonPointer } from 'json-ptr';
The API documentation is generated from code by typedoc and hosted here. Read the docs.
Documentation is always a work in progress, let us know by creating an issue if you need a scenario documented.
There are many uses for JSON Pointers, here's one we encountered when we updated a public API and suddenly had clients sending two different message bodies to our APIs. This example is contrived to illustrate how we supported both new and old incoming messages:
// examples/versions.ts
import { JsonPointer } from 'json-ptr';
export type SupportedVersion = '1.0' | '1.1';
interface PrimaryGuestNamePointers {
name: JsonPointer;
surname: JsonPointer;
honorific: JsonPointer;
}
const versions: Record<SupportedVersion, PrimaryGuestNamePointers> = {
'1.0': {
name: JsonPointer.create('/guests/0/name'),
surname: JsonPointer.create('/guests/0/surname'),
honorific: JsonPointer.create('/guests/0/honorific'),
},
'1.1': {
name: JsonPointer.create('/primary/primaryGuest/name'),
surname: JsonPointer.create('/primary/primaryGuest/surname'),
honorific: JsonPointer.create('/primary/primaryGuest/honorific'),
},
};
interface Reservation extends Record<string, unknown> {
version?: SupportedVersion;
}
/**
* Gets the primary guest's name from the specified reservation.
* @param reservation a reservation, either version 1.0 or bearing a `version`
* property indicating the version.
*/
function primaryGuestName(reservation: Reservation): string {
const pointers = versions[reservation.version || '1.0'];
if (!pointers) {
throw new Error(`Unsupported reservation version: ${reservation.version}`);
}
const name = pointers.name.get(reservation) as string;
const surname = pointers.surname.get(reservation) as string;
const honorific = pointers.honorific.get(reservation) as string;
const names: string[] = [];
if (honorific) names.push(honorific);
if (name) names.push(name);
if (surname) names.push(surname);
return names.join(' ');
}
// The original layout of a reservation (only the parts relevant to our example)
const reservationV1: Reservation = {
guests: [
{
name: 'Wilbur',
surname: 'Finkle',
honorific: 'Mr.',
},
{
name: 'Wanda',
surname: 'Finkle',
honorific: 'Mrs.',
},
{
name: 'Wilma',
surname: 'Finkle',
honorific: 'Miss',
child: true,
age: 12,
},
],
// ...
};
// The new layout of a reservation (only the parts relevant to our example)
const reservationV1_1: Reservation = {
version: '1.1',
primary: {
primaryGuest: {
name: 'Wilbur',
surname: 'Finkle',
honorific: 'Mr.',
},
additionalGuests: [
{
name: 'Wanda',
surname: 'Finkle',
honorific: 'Mrs.',
},
{
name: 'Wilma',
surname: 'Finkle',
honorific: 'Miss',
child: true,
age: 12,
},
],
// ...
},
// ...
};
console.log(primaryGuestName(reservationV1));
console.log(primaryGuestName(reservationV1_1));
prior to v3.0.0 there was a security vulnerability which allowed a developer to perform prototype pollution by sending malformed path segments to json-ptr
. If you were one of these developers, you should upgrade to v3.0.0 immediately, and stop using json-ptr
to pollute an object's prototype. If you feel you have a legitimate reason to do so, please use another method and leave json-ptr
out of it. Such behavior has been disallowed since it can easily be done using plain ol javascript by those determined to violate common best practice.
prior to v2.1.0 there was a security vulnerability which allowed an unscrupulous actor to execute arbitrary code if developers failed to sanitize user input before sending it to json-ptr
. If your code does not sanitize user input before sending it to json-ptr
, your project is vulnerable and you should upgrade to v3.0.0 immediately. And while your at it, start sanitized user input before sending it to any library!
As was rightly pointed out in this issue, I should have rolled the major version at v1.3.0
instead of the minor version due to breaking changes to the API. Not the worst blunder I've made, but my apologies all the same. Since the ship has sailed, I'm boosting the visibility of these breaking changes.
In version v1.3.0
of the library, global functions were moved to static functions of the JsonPointer
class. There should be no difference in arguments or behavior. If you were previously importing the global functions it is a small change to destructure them and have compatible code.
We're maintaining near 100% test coverage. Visit our circleci build page and drill down on a recent build's build and test step to see where we're at. It should look something like:
=============================== Coverage summary ===============================
Statements : 100% ( 270/270 )
Branches : 100% ( 172/172 )
Functions : 100% ( 49/49 )
Lines : 100% ( 265/265 )
================================================================================
We use mocha so you can also clone the code and:
$ npm install
$ npm test
Once you've run the tests on the command line you can open up ./tests.html in the browser of your choice.
WARNING! These performance metrics are quite outdated. We'll be updating as soon as we have time.
This repository has a companion repository that makes some performance comparisons between json-ptr
, jsonpointer
and json-pointer
.
All timings are expressed as nanoseconds:
.flatten(obj)
...
MODULE | METHOD | COMPILED | SAMPLES | AVG | SLOWER
json-pointer | dict | | 10 | 464455181 |
json-ptr | flatten | | 10 | 770424039 | 65.88%
jsonpointer | n/a | | - | - |
.has(obj, pointer)
...
MODULE | METHOD | COMPILED | SAMPLES | AVG | SLOWER
json-ptr | has | compiled | 1000000 | 822 |
json-ptr | has | | 1000000 | 1747 | 112.53%
json-pointer | has | | 1000000 | 2683 | 226.4%
jsonpointer | n/a | | - | - |
.has(obj, fragmentId)
...
MODULE | METHOD | COMPILED | SAMPLES | AVG | SLOWER
json-ptr | has | compiled | 1000000 | 602 |
json-ptr | has | | 1000000 | 1664 | 176.41%
json-pointer | has | | 1000000 | 2569 | 326.74%
jsonpointer | n/a | | - | - |
.get(obj, pointer)
...
MODULE | METHOD | COMPILED | SAMPLES | AVG | SLOWER
json-ptr | get | compiled | 1000000 | 590 |
json-ptr | get | | 1000000 | 1676 | 184.07%
jsonpointer | get | compiled | 1000000 | 2102 | 256.27%
jsonpointer | get | | 1000000 | 2377 | 302.88%
json-pointer | get | | 1000000 | 2585 | 338.14%
.get(obj, fragmentId)
...
MODULE | METHOD | COMPILED | SAMPLES | AVG | SLOWER
json-ptr | get | compiled | 1000000 | 587 |
json-ptr | get | | 1000000 | 1673 | 185.01%
jsonpointer | get | compiled | 1000000 | 2105 | 258.6%
jsonpointer | get | | 1000000 | 2451 | 317.55%
json-pointer | get | | 1000000 | 2619 | 346.17%
These results have been elided because there is too much detail in the actual. Your results will vary slightly depending on the resources available where you run it.
It is important to recognize in the performance results that compiled options are faster. As a general rule, you should compile any pointers you'll be using repeatedly.
2021-10-26 — 3.0.0 Potential Security Vulnerability Patched
json-ptr
to pollute an object's prototype by passing invalid path segments to the set/unset operations. This behavior has been disallowed.2021-05-14 — 2.2.0 Added Handling for Relative JSON Pointers
2021-05-12 — 2.1.1 Bug fix for #36
undefined
as intended. The original behavior has been restored.2021-05-12 — 2.1.0 Bug fixes for #28 and #30; Security Vulnerability Patched
When compiling the accessors for quickly accessing points in an object graph, the .get()
method was not properly delimiting single quotes. This error caused the get operation to throw an exception in during normal usage. Worse, in cases where malicious user input was sent directly to json-ptr
, the failure to delimit single quotes allowed the execution of arbitrary code (an injection attack). The first of these issues was reported in #28 by @mprast, the second (vulnerability) by @zpbrent. Thanks also to @elimumford for the actual code used for the fix.
If your code sent un-sanitized user input to the .get()
method of json-ptr
, your project was susceptible to this security vulnerability!
2020-10-21 — 2.0.0 Breaking Change
json-ptr
to support pointers across the prototype, I'm rolling the major version number because you're now broken.BEWARE of Breaking Changes at v1.3.0!
2020-07-20 — 1.3.2
tslib
dependency.2020-07-10 — 1.3.0 BREAKING CHANGES
JsonPointer
type. See Where did the Global Functions Go?.unset()
function contributed by @chrishalbert, updated dependencies.2019-09-14 — 1.2.0
.concat
function contributed by @vuwuv, updated dependencies.2019-03-10 — 1.1.2
2016-07-26 — 1.0.1
2016-01-12 — 1.0.0
.list(obj, fragmentId)
.2016-01-02 — 0.3.0
.list
function.map
function2014-10-21 — 0.2.0 Added #list function to enumerate all properties in a graph, producing fragmentId/value pairs.
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