JSON Patch is a neat idea for describing changes to JSON -

... the idea is that you can clean-up muddled parts of a codebase, by making data-things explicit.

it is pretty simple, and sort of beautiful.

Does the world need another json-patch implementation? no.

did I make one, and is it crappy? yes.

import { get, make, apply } = from 'garbage-patch'

let json = {
  foo: ['bar', 'baz'],
}

// apply clean changes to the json
let patch = { op: 'add', path: '/foo/-', value: 'bob' }
apply(patch, json)
/* {
  foo: ['bar', 'baz', 'bob'],
} */

// make a valid json pointer
let ptr = make(['foo', 1])
// '/foo/1'

// use it to get some data
let result = get(ptr, json)
// 'baz'

there is nothing too-clever going on. the min.js build is 2.5kb.

these methods take inspiration from the pointer spec and the patch-spec but have some differences:

1. get() is more-forgiving if you give it a path '/foo/typo/9/wrong' that doesn't exist, it will just say - 'haha! no problem! undefined! ✌'

   also, a trailing slash is allowed - /foo/

   also, a leading slash is optional - foo/1

   if you prefer, you can use an array as a pointer, too:

let json = { foo: [null, 'found'] }
let found = get(['foo', 1], json) 
// 'found'

2. apply() changes in-place (mutable) -and before you think 'hey this guy has never seen that Rich Hickey talk' - I have seen that one. most javascript implementations call .clone() over and over.

3. - sneaky-append - an 'add' patch on an array doesn't need an index, and assumes a push on an array:

let json = { foo: [1] }
// according to the spec, this must be '/foo/[index]', which seemed annoying
let patch = { op: 'add', path: '/foo', value: 2 }
json = apply(patch, json) //normally this would be an arror
// {foo: [1, 2]}

4. - sneaky-splat - an 'add' patch on an object doesn't need an key, if the value is also an object:

let json = { foo: { bar: true } }
let patch = { op: 'add', path: '/foo', value: { baz: true } }
apply(patch, json) //this would normally be an error, i think.
// { foo: { bar: true, baz: true } }

API

• make(props) - create a JSON pointer from a list of properties
• get(pntr,json) - use a pointer to get data out of JSON
• apply(patch, json) - make modifications to a JSON object (in place)

all the different build formats are in ./builds there's a get only build, that is < 1kb:

import { get } from 'garbage-patch'

const get = require('garbage-patch/get')

See Also

• json-patch - 7kb
• fast-json-patch - 12kb
• json-8 - 11kb
• jiff - 12kb

MIT