JSON Pointer

This is an implementation of RFC-6901 JSON Pointer. JSON Pointer is designed for referring to data values within a JSON document. It's designed to be URL friendly so it can be used as a URL fragment that points to a specific part of the JSON document.

Installation

Includes support for node.js (ES Modules, TypeScript) and browsers.

1npm install @hyperjump/json-pointer

Usage

1import * as JsonPointer from "@hyperjump/json-pointer";
2
3const value = {
4  "foo": {
5    "bar": 42
6  }
7};
8
9// Construct pointers
10const fooPointer = JsonPointer.append("foo", JsonPointer.nil); // "/foo"
11const fooBarPointer = JsonPointer.append(fooPointer, "bar"); // "/foo/bar"
12
13// Get a value from a pointer
14const getFooBar = JsonPointer.get(fooBarPointer);
15getFooBar(value); // 42
16
17// Set a value from a pointer
18// New value is returned without modifying the original
19const setFooBar = JsonPointer.set(fooBarPointer);
20setFooBar(value, 33); // { "foo": { "bar": 33 } }
21
22// Assign a value from a pointer
23// The original value is changed and no value is returned
24const assignFooBar = JsonPointer.assign(fooBarPointer);
25assignFooBar(value, 33); // { "foo": { "bar": 33 } }
26
27// Unset a value from a pointer
28// New value is returned without modifying the original
29const unsetFooBar = JsonPointer.unset(fooBarPointer);
30setFooBar(value); // { "foo": {} }
31
32// Delete a value from a pointer
33// The original value is changed and no value is returned
34const deleteFooBar = JsonPointer.remove(fooBarPointer);
35deleteFooBar(value); // { "foo": {} }

API

• nil: ""

  The empty pointer.

• pointerSegments: (pointer: string) => Generator<string>

  An iterator for the segments of a JSON Pointer that handles escaping.

• append: (segment: string, pointer: string) => string

  Append a segment to a JSON Pointer.

• get: (pointer: string, subject: any) => any

  Use a JSON Pointer to get a value. This function can be curried.

• set: (pointer: string, subject: any, value: any) => any

  Immutably set a value using a JSON Pointer. Returns a new version of subject with the value set. The original subject is not changed, but the value isn't entirely cloned. Values that aren't changed will point to the same value as the original. This function can be curried.

• assign: (pointer: string, subject: any, value: any) => void

  Mutate a value using a JSON Pointer. This function can be curried.

• unset: (pointer: string, subject: any) => any

  Immutably delete a value using a JSON Pointer. Returns a new version of subject without the value. The original subject is not changed, but the value isn't entirely cloned. Values that aren't changed will point to the same value as the original. This function can be curried.

• remove: (pointer: string, subject: any) => void

  Delete a value using a JSON Pointer. This function can be curried.

Contributing

Tests

Run the tests

1npm test

Run the tests with a continuous test runner

1npm test -- --watch