Diff-ing algorithm

.gitignore

@@ -0,0 +1,19 @@
+# IDE
+.idea/
+.vscode/
+
+# Logs
+*.log*
+yarn.lock
+package-lock.json
+
+# Misc
+examples
+notes.md
+node_modules
+coverage
+*.xml
+
+# Dist
+*.gz
+dist/

package.json

@@ -0,0 +1,35 @@
+{
+  "name": "trdis",
+  "version": "0.0.0",
+  "description": "The most known way to travel in space and time",
+  "license": "MIT",
+  "repository": "Swizz/trdis",
+  "author": "Quentin Gerodel",
+  "keywords": [
+    "trdis",
+    "timetravel",
+    "object",
+    "state",
+    "do",
+    "undo",
+    "diff",
+    "json"
+  ],
+  "main": "dist/trdis.js",
+  "module": "src/index.js",
+  "files": [
+    "src",
+    "dist"
+  ],
+  "scripts": {
+    "build": "npm run bundle && npm run minify",
+    "bundle": "rollup -i src/index.js -o dist/trdis.js -m -f umd -n trdis",
+    "format": "prettier --semi false --write 'src/**/*.js'",
+    "minify": "uglifyjs dist/trdis.js -o dist/trdis.js --mangle --compress --source-map"
+  },
+  "devDependencies": {
+    "prettier": "^1.8.1",
+    "rollup": "^0.50.0",
+    "uglify-js": "^3.1.8"
+  }
+}

src/index.js

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+export function diff(from, to) {
+  var done = {}
+  var patch = {
+    do: {},
+    undo: {}
+  }
+
+  for (var key in to) {
+    if (key in done || from[key] === to[key]) continue
+
+    patch.do[key] = to[key]
+    patch.undo[key] = from[key]
+
+    done[key] = true
+  }
+
+  for (var key in from) {
+    if (key in done || from[key] === to[key]) continue
+
+    patch.do[key] = to[key]
+    patch.undo[key] = from[key]
+
+    done[key] = true
+  }
+
+  return patch
+}