Implement toMatchDiffSnapshot jest matcher.

README.md

@@ -11,10 +11,12 @@ yarn add --dev snapshot-diff
 
 ## Usage
 
+##### With default jest matcher
+
 ```js
 const snapshotDiff = require('snapshot-diff');
 
-test('snapshot difference between 2 strings', () => {
+test('snapshot difference between 2 strings', () => {  
   expect(snapshotDiff(a, b)).toMatchSnapshot();
 });
 
@@ -31,7 +33,33 @@ test('snapshot difference between 2 React components state', () => {
 });
 ```
 
+##### With custom matcher
+
+```js
+const { toMatchDiffSnapshot } = require('snapshot-diff');
+
+expect.extend({ toMatchDiffSnapshot });
+
+test('snapshot difference between 2 strings', () => { 
+  expect(a).toMatchDiffSnapshot(b);
+});
+
+const React = require('react');
+const Component = require('./Component');
+
+test('snapshot difference between 2 React components state', () => { 
+  expect(
+    <Component test="say" />
+  ).toMatchDiffSnapshot(
+    <Component test="my name" />
+  );    
+});
+```
+
+
+
 Produced snapshot:
+
 ```diff
 exports[`snapshot difference between 2 strings 1`] = `
 "- First value

__tests__/__snapshots__/toMatchDiffSnapshot.test.js.snap

@@ -0,0 +1,60 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`proxies "colors" option(s) 1`] = `
+"- First value
++ Second value
+
+@@ -5,8 +5,9 @@
+     some
+     some
+     some
+     some
+     not
++    so
+     very
+     long
+     script"
+`;
+
+exports[`proxies "contextLines" option(s) 1`] = `
+"- First value
++ Second value
+
+@@ -10,0 +10,1 @@
++    so"
+`;
+
+exports[`proxies "expand" option(s) 1`] = `
+"- First value
++ Second value
+
+
+      some
+      some
+      some
+      some
+      some
+      some
+      some
+      not
++     so
+      very
+      long
+      script"
+`;
+
+exports[`works with default options 1`] = `
+"- First value
++ Second value
+
+@@ -5,8 +5,9 @@
+     some
+     some
+     some
+     some
+     not
++    so
+     very
+     long
+     script"
+`;

__tests__/index.test.js

@@ -0,0 +1,12 @@
+test('public api', () => {
+  const index = require('../src/index');
+
+  expect(index).toBeInstanceOf(Function);
+  expect(index.snapshotDiff).toBe(index);
+  expect(index.toMatchDiffSnapshot).toBeInstanceOf(Function);
+
+  const { snapshotDiff, toMatchDiffSnapshot } = require('../src/index');
+
+  expect(snapshotDiff).toBe(index);
+  expect(toMatchDiffSnapshot).toBe(index.toMatchDiffSnapshot);
+});

__tests__/toMatchDiffSnapshot.test.js

@@ -0,0 +1,51 @@
+// @flow
+
+const snapshotDiff = require('../src/index');
+
+const a = `
+    some
+    some
+    some
+    some
+    some
+    some
+    some
+    not
+    very
+    long
+    script
+`;
+const b = `
+    some
+    some
+    some
+    some
+    some
+    some
+    some
+    not
+    so
+    very
+    long
+    script
+`;
+
+beforeAll(() => {
+  expect.extend({ toMatchDiffSnapshot: snapshotDiff.toMatchDiffSnapshot });
+});
+
+test('works with default options', () => {
+  // $FlowFixMe
+  expect(a).toMatchDiffSnapshot(b);
+});
+
+[
+  { expand: true },
+  { colors: true },
+  { contextLines: 0 },
+].forEach((options: any) => {
+  test(`proxies "${Object.keys(options).join(', ')}" option(s)`, () => {
+    // $FlowFixMe
+    expect(a).toMatchDiffSnapshot(b, options);
+  });
+});

index.d.ts

@@ -0,0 +1,13 @@
+/// <reference types="jest"/>
+
+type DiffOptions = {
+  expand?: boolean,
+  colors?: boolean,
+  contextLines?: number,
+};
+
+declare namespace jest {
+  interface Matchers {
+    toMatchDiffSnapshot(valueB: any, options?: DiffOptions): boolean
+  }
+}

package.json

@@ -3,6 +3,7 @@
   "version": "0.0.5",
   "description": "Diffing Jest snapshots utility",
   "main": "build/index.js",
+  "typings": "index.d.ts",
   "license": "MIT",
   "author": "Michał Pierzchała <[email protected]>",
   "scripts": {
@@ -20,6 +21,7 @@
   },
   "dependencies": {
     "jest-diff": "test",
+    "jest-snapshot": "test",
     "pretty-format": "^20.0.3",
     "strip-ansi": "^4.0.0"
   },

src/index.js

@@ -3,6 +3,7 @@
 'use strict';
 
 const diff = require('jest-diff');
+const snapshot = require('jest-snapshot');
 const prettyFormat = require('pretty-format');
 
 const { ReactElement } = prettyFormat.plugins;
@@ -64,4 +65,12 @@ function diffReactComponents(valueA: any, valueB: any, options: Options) {
   });
 }
 
+function toMatchDiffSnapshot(valueA: any, valueB: any, options?: Options) {
+  const difference = snapshotDiff(valueA, valueB, options);
+
+  return snapshot.toMatchSnapshot.call(this, difference);
+}
+
 module.exports = snapshotDiff;
+module.exports.snapshotDiff = snapshotDiff;
+module.exports.toMatchDiffSnapshot = toMatchDiffSnapshot;

yarn.lock

@@ -2124,6 +2124,16 @@ [email protected], jest-diff@test:
     jest-matcher-utils "20.1.0-delta.5"
     pretty-format "20.1.0-delta.5"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-diff/-/jest-diff-20.1.0-echo.1.tgz#7306889a65d58a86e5b6e3027f985c446d46c511"
+  dependencies:
+    chalk "^2.0.1"
+    diff "^3.2.0"
+    jest-get-type "20.1.0-echo.1"
+    jest-matcher-utils "20.1.0-echo.1"
+    pretty-format "20.1.0-echo.1"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-docblock/-/jest-docblock-20.1.0-delta.5.tgz#a3699e999a4be26beee576a41988bd9c782cb469"
@@ -2151,6 +2161,10 @@ [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-20.1.0-delta.5.tgz#3a6a0c38e2eb4da3082a4a0175ae0c4a18865c91"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-20.1.0-echo.1.tgz#00e3a07d5feffc76236488aa4445bd18e66e71ac"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-haste-map/-/jest-haste-map-20.1.0-delta.5.tgz#bc2cccc0970541d752af18688ca50235f95a1e06"
@@ -2182,6 +2196,14 @@ [email protected]:
     jest-get-type "20.1.0-delta.5"
     pretty-format "20.1.0-delta.5"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-matcher-utils/-/jest-matcher-utils-20.1.0-echo.1.tgz#2bbb22b2e6269a87e73c152003dc91abb8ef0c85"
+  dependencies:
+    chalk "^2.0.1"
+    jest-get-type "20.1.0-echo.1"
+    pretty-format "20.1.0-echo.1"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-matchers/-/jest-matchers-20.1.0-delta.5.tgz#31f6f556b94709083012eb0b85bb384126b33651"
@@ -2200,10 +2222,22 @@ [email protected]:
     micromatch "^2.3.11"
     slash "^1.0.0"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-message-util/-/jest-message-util-20.1.0-echo.1.tgz#31b6cced3e8cec6e1a74e7bcc989b987ea2b0ed5"
+  dependencies:
+    chalk "^2.0.1"
+    micromatch "^2.3.11"
+    slash "^1.0.0"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-mock/-/jest-mock-20.1.0-delta.5.tgz#220bc3bd2272dc57444f20602c65f15b769d7241"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-mock/-/jest-mock-20.1.0-echo.1.tgz#c37e47c954aa5090e887d50ba96f3b1d51d3bf90"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-regex-util/-/jest-regex-util-20.1.0-delta.5.tgz#ad30d52b16e505c793a16ca73aa37e4852b24858"
@@ -2255,6 +2289,17 @@ [email protected]:
     natural-compare "^1.4.0"
     pretty-format "20.1.0-delta.5"
 
+jest-snapshot@test:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-snapshot/-/jest-snapshot-20.1.0-echo.1.tgz#580c8064b6516a5a29ef6dfa14432c5071562155"
+  dependencies:
+    chalk "^2.0.1"
+    jest-diff "20.1.0-echo.1"
+    jest-matcher-utils "20.1.0-echo.1"
+    jest-util "20.1.0-echo.1"
+    natural-compare "^1.4.0"
+    pretty-format "20.1.0-echo.1"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-util/-/jest-util-20.1.0-delta.5.tgz#45f1247608b98cc0a0fe1ae643e747f2dd60e40f"
@@ -2267,6 +2312,18 @@ [email protected]:
     leven "^2.1.0"
     mkdirp "^0.5.1"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-util/-/jest-util-20.1.0-echo.1.tgz#adec8947191e31e2be5e243bffd28742e94f9401"
+  dependencies:
+    chalk "^2.0.1"
+    graceful-fs "^4.1.11"
+    jest-message-util "20.1.0-echo.1"
+    jest-mock "20.1.0-echo.1"
+    jest-validate "20.1.0-echo.1"
+    leven "^2.1.0"
+    mkdirp "^0.5.1"
+
 [email protected]:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest-validate/-/jest-validate-20.1.0-delta.5.tgz#f5d1dffc5cf7acbfe353f0062e2a9548ef7f1388"
@@ -2276,6 +2333,15 @@ [email protected]:
     leven "^2.1.0"
     pretty-format "20.1.0-delta.5"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/jest-validate/-/jest-validate-20.1.0-echo.1.tgz#eb1d795a9a67a3e2e1e838b16d7b8e298d597d51"
+  dependencies:
+    chalk "^2.0.1"
+    jest-get-type "20.1.0-echo.1"
+    leven "^2.1.0"
+    pretty-format "20.1.0-echo.1"
+
 jest@test:
   version "20.1.0-delta.5"
   resolved "https://registry.yarnpkg.com/jest/-/jest-20.1.0-delta.5.tgz#7bca864f549fb4b40049a094ef2a0accb3097e92"
@@ -2808,6 +2874,13 @@ [email protected]:
     ansi-regex "^3.0.0"
     ansi-styles "^3.0.0"
 
+[email protected]:
+  version "20.1.0-echo.1"
+  resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-20.1.0-echo.1.tgz#3b97907461d90a06b2e7531185cb1b529eb186f3"
+  dependencies:
+    ansi-regex "^3.0.0"
+    ansi-styles "^3.0.0"
+
 pretty-format@^20.0.3:
   version "20.0.3"
   resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-20.0.3.tgz#020e350a560a1fe1a98dc3beb6ccffb386de8b14"