immutable-json-pointer

JSON Pointer (RFC6901) implementation for Node.js

Mutate a copy of data without changing the original source.

Install

// NPM
$ npm install immutable-json-pointer

// yarn v2
$ yarn add immutable-json-pointer

Usage

get

import { get } from "immutable-json-pointer";
// For example, given the JSON document
const json = {
  foo: ["bar", "baz"],
  "": 0,
  "a/b": 1,
  "c%d": 2,
  "e^f": 3,
  "g|h": 4,
  "i\\j": 5,
  'k"l': 6,
  " ": 7,
  "m~n": 8,
};
//   The following JSON strings evaluate to the accompanying values:
expect(get(json, "")).toBe(json); // the whole document
expect(get(json, "/foo")).toStrictEqual(["bar", "baz"]);
expect(get(json, "/foo/0")).toBe("bar");
expect(get(json, "/")).toBe(0);
expect(get(json, "/a~1b")).toBe(1);
expect(get(json, "/c%d")).toBe(2);
expect(get(json, "/e^f")).toBe(3);
expect(get(json, "/g|h")).toBe(4);
expect(get(json, "/i\\j")).toBe(5);
expect(get(json, '/k"l')).toBe(6);
expect(get(json, "/ ")).toBe(7);
expect(get(json, "/m~0n")).toBe(8);

set

import { set } from "immutable-json-pointer";
// For example, given the JSON document
const json = {
  foo: ["bar", "baz"],
  hoge: {
    fuga: "piyo",
  },
};
const newJson = set(json, "/foo/-", "boss");

expect(newJson === json).toBeFalsy();
expect(newJson.hoge === json.hoge).toBeTruthy();
expect(newJson.foo === json.foo).toBeFalsy();
expect(newJson.foo[2]).toBe("boss");

has

import { has } from "immutable-json-pointer";
const json = {
  value: 1,
};
has(json, "/value"); // true
has(json, "/item"); // false

read

import { read } from "immutable-json-pointer";
const json = {
  value: 1,
};
read(json, "/value"); // 1
read(json, "/item"); // undefined

remove

import { remove } from "immutable-json-pointer";
const json = {
  unused: 0,
  value: 1,
};
const newJson = remove(json, "/unused");
console.log(newJSON); // { value: 1 }
console.log(json); // { unused: 0, value: 1 }

dict

import { dict } from "immutable-json-pointer";
const json = {
  item: 0,
  value: 1,
};
const dic = dict(json);
console.log(dic); // { '/item': 0, '/value': 1 }

compile

import { compile } from "immutable-json-pointer";
console.log(compile(["a", "b", "c"])); // "/a/b/c"

transform

import { transform } from "immutable-json-pointer";
const json = {
  value: 0,
};
const nextValue = 1;
const json2 = transform(json, "/value", (prev, path) => {
  if (prev != nextValue) {
    return nextValue;
  }
  return prev;
});
console.log(json); // { "value": 0 }
console.log(json2); // { "value": 1 }

chain

import { chain } from "immutable-json-pointer";
const doc = {
  foo: {
    bar: {
      baz: 1,
    },
  },
};
const operation = chain<typeof doc>(
  (doc) => set(doc, "/foo/bar/baz", 2),
  (doc) => set(doc, "/foo/bar/baz", 3),
  (doc) => set(doc, "/foo/bar/baz", 4)
);
const result = operation(doc);
console.log(result); // { foo:{ bar: { baz: 4 } } }