JSON-Patch =============== > A leaner and meaner implementation of JSON-Patch. Small footprint. High performance. [![Build Status](https://travis-ci.org/Starcounter-Jack/JSON-Patch.svg?branch=master)](https://travis-ci.org/Starcounter-Jack/JSON-Patch) With JSON-Patch, you can: - **apply** patches (arrays) and single operations on JS object - **validate** a sequence of patches - **observe** for changes and **generate** patches when a change is detected - **compare** two objects to obtain the difference Tested in Firefox, Chrome, Edge, Safari, IE11, Deno and Node.js ## Why you should use JSON-Patch JSON-Patch [(RFC6902)](http://tools.ietf.org/html/rfc6902) is a standard format that allows you to update a JSON document by sending the changes rather than the whole document. JSON Patch plays well with the HTTP PATCH verb (method) and REST style programming. Mark Nottingham has a [nice blog]( http://www.mnot.net/blog/2012/09/05/patch) about it. ## Install [Download as ZIP](https://github.com/Starcounter-Jack/JSON-Patch/archive/master.zip) or install the current version using a package manager (and save it as a dependency): ```sh # NPM npm install fast-json-patch --save ``` ## Adding to your project ### In a web browser Load the bundled distribution script: ```html ``` In [browsers that support ECMAScript modules](https://caniuse.com/#feat=es6-module), the below code uses this library as a module: ```html ``` ### In Node.js In Node 12+ with `--experimental-modules` flag, the below code uses this library as an ECMAScript module: ```js import * as jsonpatch from 'fast-json-patch/index.mjs'; import { applyOperation } from 'fast-json-patch/index.mjs'; ``` In Webpack (and most surely other bundlers based on Babel), the below code uses this library as an ECMAScript module: ```js import * as jsonpatch from 'fast-json-patch'; import { applyOperation } from 'fast-json-patch'; ``` In standard Node, the below code uses this library as a CommonJS module: ```js const { applyOperation } = require('fast-json-patch'); const applyOperation = require('fast-json-patch').applyOperation; ``` ## Directories Directories used in this package: - `dist/` - contains ES5 files for a Web browser - `commonjs/` - contains CommonJS module and typings - `module/` - contains ECMAScript module and typings - `src/` - contains TypeScript source files ## API #### `function applyPatch(document: T, patch: Operation[], validateOperation?: boolean | Validator, mutateDocument: boolean = true, banPrototypeModifications: boolean = true): PatchResult` Applies `patch` array on `obj`. - `document` The document to patch - `patch` a JSON-Patch array of operations to apply - `validateOperation` Boolean for whether to validate each operation with our default validator, or to pass a validator callback - `mutateDocument` Whether to mutate the original document or clone it before applying - `banPrototypeModifications` Whether to ban modifications to `__proto__`, defaults to `true`. An invalid patch results in throwing an error (see `jsonpatch.validate` for more information about the error object). It modifies the `document` object and `patch` - it gets the values by reference. If you would like to avoid touching your `patch` array values, clone them: `jsonpatch.applyPatch(document, jsonpatch.deepClone(patch))`. Returns an array of [`OperationResult`](#operationresult-type) objects - one item for each item in `patches`, each item is an object `{newDocument: any, test?: boolean, removed?: any}`. * `test` - boolean result of the test * `remove`, `replace` and `move` - original object that has been removed * `add` (only when adding to an array) - index at which item has been inserted (useful when using `-` alias) - ** Note: It throws `TEST_OPERATION_FAILED` error if `test` operation fails. ** - ** Note II: the returned array has `newDocument` property that you can use as the final state of the patched document **. - ** Note III: By default, when `banPrototypeModifications` is `true`, this method throws a `TypeError` when you attempt to modify an object's prototype. - See [Validation notes](#validation-notes). Example: ```js var document = { firstName: "Albert", contactDetails: { phoneNumbers: [] } }; var patch = [ { op: "replace", path: "/firstName", value: "Joachim" }, { op: "add", path: "/lastName", value: "Wester" }, { op: "add", path: "/contactDetails/phoneNumbers/0", value: { number: "555-123" } } ]; document = jsonpatch.applyPatch(document, patch).newDocument; // document == { firstName: "Joachim", lastName: "Wester", contactDetails: { phoneNumbers: [{number:"555-123"}] } }; ``` #### `function applyOperation(document: T, operation: Operation, validateOperation: boolean | Validator = false, mutateDocument: boolean = true, banPrototypeModifications: boolean = true, index: number = 0): OperationResult` Applies single operation object `operation` on `document`. - `document` The document to patch - `operation` The operation to apply - `validateOperation` Whether to validate the operation, or to pass a validator callback - `mutateDocument` Whether to mutate the original document or clone it before applying - `banPrototypeModifications` Whether to ban modifications to `__proto__`, defaults to `true`. - `index` The index of the operation in your patch array. Useful for better error reporting when that operation fails to apply. It modifies the `document` object and `operation` - it gets the values by reference. If you would like to avoid touching your values, clone them: `jsonpatch.applyOperation(document, jsonpatch.deepClone(operation))`. Returns an [`OperationResult`](#operationresult-type) object `{newDocument: any, test?: boolean, removed?: any}`. - ** Note: It throws `TEST_OPERATION_FAILED` error if `test` operation fails. ** - ** Note II: By default, when `banPrototypeModifications` is `true`, this method throws a `TypeError` when you attempt to modify an object's prototype. - See [Validation notes](#validation-notes). Example: ```js var document = { firstName: "Albert", contactDetails: { phoneNumbers: [] } }; var operation = { op: "replace", path: "/firstName", value: "Joachim" }; document = jsonpatch.applyOperation(document, operation).newDocument; // document == { firstName: "Joachim", contactDetails: { phoneNumbers: [] }} ``` #### `jsonpatch.applyReducer(document: T, operation: Operation, index: number): T` **Ideal for `patch.reduce(jsonpatch.applyReducer, document)`**. Applies single operation object `operation` on `document`. Returns the a modified document. Note: It throws `TEST_OPERATION_FAILED` error if `test` operation fails. Example: ```js var document = { firstName: "Albert", contactDetails: { phoneNumbers: [ ] } }; var patch = [ { op:"replace", path: "/firstName", value: "Joachim" }, { op:"add", path: "/lastName", value: "Wester" }, { op:"add", path: "/contactDetails/phoneNumbers/0", value: { number: "555-123" } } ]; var updatedDocument = patch.reduce(applyReducer, document); // updatedDocument == { firstName:"Joachim", lastName:"Wester", contactDetails:{ phoneNumbers[ {number:"555-123"} ] } }; ``` #### `jsonpatch.deepClone(value: any): any` Returns deeply cloned value. #### `jsonpatch.escapePathComponent(path: string): string` Returns the escaped path. #### `jsonpatch.unescapePathComponent(path: string): string` Returns the unescaped path. #### `jsonpatch.getValueByPointer(document: object, pointer: string)` Retrieves a value from a JSON document by a JSON pointer. Returns the value. #### `jsonpatch.observe(document: any, callback?: Function): Observer` Sets up an deep observer on `document` that listens for changes in object tree. When changes are detected, the optional callback is called with the generated patches array as the parameter. Returns `observer`. #### `jsonpatch.generate(document: any, observer: Observer, invertible = false): Operation[]` If there are pending changes in `obj`, returns them synchronously. If a `callback` was defined in `observe` method, it will be triggered synchronously as well. If `invertible` is true, then each change will be preceded by a test operation of the value before the change. If there are no pending changes in `obj`, returns an empty array (length 0). Example: ```js var document = { firstName: "Joachim", lastName: "Wester", contactDetails: { phoneNumbers: [ { number:"555-123" }] } }; var observer = jsonpatch.observe(document); document.firstName = "Albert"; document.contactDetails.phoneNumbers[0].number = "123"; document.contactDetails.phoneNumbers.push({ number:"456" }); var patch = jsonpatch.generate(observer); // patch == [ // { op: "replace", path: "/firstName", value: "Albert"}, // { op: "replace", path: "/contactDetails/phoneNumbers/0/number", value: "123" }, // { op: "add", path: "/contactDetails/phoneNumbers/1", value: {number:"456"}} // ]; ``` Example of generating patches with test operations for values in the first object: ```js var document = { firstName: "Joachim", lastName: "Wester", contactDetails: { phoneNumbers: [ { number:"555-123" }] } }; var observer = jsonpatch.observe(document); document.firstName = "Albert"; document.contactDetails.phoneNumbers[0].number = "123"; document.contactDetails.phoneNumbers.push({ number:"456" }); var patch = jsonpatch.generate(observer, true); // patch == [ // { op: "test", path: "/firstName", value: "Joachim"}, // { op: "replace", path: "/firstName", value: "Albert"}, // { op: "test", path: "/contactDetails/phoneNumbers/0/number", value: "555-123" }, // { op: "replace", path: "/contactDetails/phoneNumbers/0/number", value: "123" }, // { op: "add", path: "/contactDetails/phoneNumbers/1", value: {number:"456"}} // ]; ``` #### `jsonpatch.unobserve(document, observer)` ```typescript jsonpatch.unobserve(document: any, observer: Observer): void type JsonableObj = { [key:string]: Jsonable }; type JsonableArr = Jsonable[]; type Jsonable = JsonableArr | JsonableObj | string | number | boolean | null; ``` Destroys the observer set up on `document`. Any remaining changes are delivered synchronously (as in `jsonpatch.generate`). Note: this is different that ES6/7 `Object.unobserve`, which delivers remaining changes asynchronously. #### `jsonpatch.compare(document1, document2, invertible)` ```typescript jsonpatch.compare(document1: Jsonable, document2: Jsonable, invertible = false): Operation[] type JsonableObj = { [key:string]: Jsonable }; type JsonableArr = Jsonable[]; type Jsonable = JsonableArr | JsonableObj | string | number | boolean | null; ``` Compares object trees `document1` and `document2` and returns the difference relative to `document1` as a patches array. If `invertible` is true, then each change will be preceded by a test operation of the value in `document1`. If there are no differences, returns an empty array (length 0). Example: ```js var documentA = {user: {firstName: "Albert", lastName: "Einstein"}}; var documentB = {user: {firstName: "Albert", lastName: "Collins"}}; var diff = jsonpatch.compare(documentA, documentB); //diff == [{op: "replace", path: "/user/lastName", value: "Collins"}] ``` Example of comparing two object trees with test operations for values in the first object: ```js var documentA = {user: {firstName: "Albert", lastName: "Einstein"}}; var documentB = {user: {firstName: "Albert", lastName: "Collins"}}; var diff = jsonpatch.compare(documentA, documentB, true); //diff == [ // {op: "test", path: "/user/lastName", value: "Einstein"}, // {op: "replace", path: "/user/lastName", value: "Collins"} // ]; ``` #### `jsonpatch.validate(patch: Operation[], document?: any, validator?: Function): JsonPatchError` See [Validation notes](#validation-notes) Validates a sequence of operations. If `document` parameter is provided, the sequence is additionally validated against the object tree. If there are no errors, returns undefined. If there is an errors, returns a JsonPatchError object with the following properties: - `name` String - short error code - `message` String - long human readable error message - `index` Number - index of the operation in the sequence - `operation` Object - reference to the operation - `tree` Object - reference to the tree Possible errors: Error name | Error message ------------------------------|------------ SEQUENCE_NOT_AN_ARRAY | Patch sequence must be an array OPERATION_NOT_AN_OBJECT | Operation is not an object OPERATION_OP_INVALID | Operation `op` property is not one of operations defined in RFC-6902 OPERATION_PATH_INVALID | Operation `path` property is not a valid string OPERATION_FROM_REQUIRED | Operation `from` property is not present (applicable in `move` and `copy` operations) OPERATION_VALUE_REQUIRED | Operation `value` property is not present, or `undefined` (applicable in `add`, `replace` and `test` operations) OPERATION_VALUE_CANNOT_CONTAIN_UNDEFINED | Operation `value` property object has at least one `undefined` value (applicable in `add`, `replace` and `test` operations) OPERATION_PATH_CANNOT_ADD | Cannot perform an `add` operation at the desired path OPERATION_PATH_UNRESOLVABLE | Cannot perform the operation at a path that does not exist OPERATION_FROM_UNRESOLVABLE | Cannot perform the operation from a path that does not exist OPERATION_PATH_ILLEGAL_ARRAY_INDEX | Expected an unsigned base-10 integer value, making the new referenced value the array element with the zero-based index OPERATION_VALUE_OUT_OF_BOUNDS | The specified index MUST NOT be greater than the number of elements in the array TEST_OPERATION_FAILED | When operation is `test` and the test fails, applies to `applyReducer`. Example: ```js var obj = {user: {firstName: "Albert"}}; var patches = [{op: "replace", path: "/user/firstName", value: "Albert"}, {op: "replace", path: "/user/lastName", value: "Einstein"}]; var errors = jsonpatch.validate(patches, obj); if (errors.length == 0) { //there are no errors! } else { for (var i=0; i < errors.length; i++) { if (!errors[i]) { console.log("Valid patch at index", i, patches[i]); } else { console.error("Invalid patch at index", i, errors[i], patches[i]); } } } ``` ## `OperationResult` Type Functions `applyPatch` and `applyOperation` both return `OperationResult` object. This object is: ```ts {newDocument: any, test?: boolean, removed?: any} ``` Where: - `newDocument`: the new state of the document after the patch/operation is applied. - `test`: if the operation was a `test` operation. This will be its result. - `removed`: contains the removed, moved, or replaced values from the document after a `remove`, `move` or `replace` operation. ## Validation Notes Functions `applyPatch`, `applyOperation`, and `validate` accept a `validate`/ `validator` parameter: - If the `validateOperation` parameter is set to `false`, validation will not occur. - If set to `true`, the patch is extensively validated before applying using jsonpatch's default validation. - If set to a `function` callback, the patch is validated using that function. If you pass a validator, it will be called with four parameters for each operation, `function(operation, index, tree, existingPath)` and it is expected to throw `JsonPatchError` when your conditions are not met. - `operation` The operation it self. - `index` `operation`'s index in the patch array (if application). - `tree` The object that is supposed to be patched. - `existingPath` the path `operation` points to. ## Overwriting and `move` Operation When the target of the move operation already exists, it is cached, deep cloned and returned as `removed` in `OperationResult`. ## `undefined`s (JS to JSON projection) As `undefined` type does not exist in JSON, it's also not a valid value of JSON Patch operation. Therefore `jsonpatch` will not generate JSON Patches that sets anything to `undefined`. Whenever a value is set to `undefined` in JS, JSON-Patch methods `generate` and `compare` will treat it similarly to how JavaScript method [`JSON.stringify` (MDN)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify) treats them: > If `undefined` (...) is encountered during conversion it is either omitted (when it is found in an object) or censored to `null` (when it is found in an array). See the [ECMAScript spec](http://www.ecma-international.org/ecma-262/6.0/index.html#sec-json.stringify) for details. ## Specs/tests - [Run in browser](http://starcounter-jack.github.io/JSON-Patch/test/) ## [Contributing](CONTRIBUTING.md) ## Changelog To see the list of recent changes, see [Releases](https://github.com/Starcounter-Jack/JSON-Patch/releases). ## Footprint 4 KB minified and gzipped (12 KB minified) ## Performance ##### [`add` benchmark](https://run.perf.zone/view/JSON-Patch-Add-Operation-1535541298893) ![image](https://user-images.githubusercontent.com/17054134/44784357-aa422480-ab8d-11e8-8a7e-037e692dd842.png) ##### [`replace` benchmark](https://run.perf.zone/view/JSON-Patch-Replace-Operation-1535540952263) ![image](https://user-images.githubusercontent.com/17054134/44784275-5fc0a800-ab8d-11e8-8a90-e87b8d5409d0.png) Tested on 29.08.2018. Compared libraries: - [Starcounter-Jack/JSON-Patch](https://www.npmjs.com/package/fast-json-patch) 2.0.6 - [bruth/jsonpatch-js](https://www.npmjs.com/package/json-patch) 0.7.0 - [dharmafly/jsonpatch.js](https://www.npmjs.com/package/jsonpatch) 3.0.1 - [jiff](https://www.npmjs.com/package/jiff) 0.7.3 - [RFC6902](https://www.npmjs.com/package/rfc6902) 2.4.0 We aim the tests to be fair. Our library puts performance as the #1 priority, while other libraries can have different priorities. If you'd like to update the benchmarks or add a library, please fork the [perf.zone](https://perf.zone) benchmarks linked above and open an issue to include new results. ## License MIT

	Stars	Issues	Version	Updated	Created
fast-json-patch	1,754	75	3.1.1	2 years ago	11 years ago
jsondiffpatch	4,683	83	0.6.0	5 months ago	12 years ago
jsonpatch			3.1.0	2 years ago	13 years ago
object-diff	43	0	0.0.4	7 years ago	10 years ago

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