From 8360da72cb9e5120a45acbe483764ce5a18e4449 Mon Sep 17 00:00:00 2001
From: cha0s <git@cha0s.io>
Date: Fri, 17 May 2019 04:31:37 -0500
Subject: [PATCH] feat: merge and mergeDiff

---
 packages/core/index.js      |  7 ++++++
 packages/core/merge-diff.js | 49 +++++++++++++++++++++++++++++++++++++
 packages/core/merge.js      | 10 ++++++++
 packages/core/package.json  |  7 ++++--
 4 files changed, 71 insertions(+), 2 deletions(-)
 create mode 100644 packages/core/merge-diff.js
 create mode 100644 packages/core/merge.js

diff --git a/packages/core/index.js b/packages/core/index.js
index 1ee1481..924ee4e 100644
--- a/packages/core/index.js
+++ b/packages/core/index.js
@@ -69,5 +69,12 @@ export class TickingPromise extends Promise {
 }
 
 export {EventEmitterMixin as EventEmitter} from './event-emitter';
+export {merge} from './merge';
+export {
+  mergeDiff,
+  mergeDiffArray,
+  mergeDiffObject,
+  mergeDiffPrimitive,
+} from './merge-diff';
 export {fastApply} from './fast-apply';
 export {PropertyMixin as Property} from './property';
diff --git a/packages/core/merge-diff.js b/packages/core/merge-diff.js
new file mode 100644
index 0000000..9b4f2a8
--- /dev/null
+++ b/packages/core/merge-diff.js
@@ -0,0 +1,49 @@
+
+export function mergeDiffArray(pristine, current) {
+  if (!Array.isArray(pristine)) {
+    return current;
+  }
+  if (pristine.length !== current.length) {
+    return current;
+  }
+  for (let i = 0; i < pristine.length; i++) {
+    if (JSON.stringify(current[i]) !== JSON.stringify(pristine[i])) {
+      return current;
+    }
+  }
+}
+
+export function mergeDiffObject(pristine, current) {
+  if ('object' !== typeof pristine) {
+    return current;
+  }
+  const diff = {};
+  for (const i in current) {
+    const value = mergeDiff(pristine[i], current[i]);
+    if (undefined !== value) {
+      diff[i] = value;
+    }
+  }
+  if (0 === Object.keys(diff).length) {
+    return undefined;
+  }
+  return diff;
+}
+
+export function mergeDiffPrimitive(pristine, current) {
+  if (pristine !== current) {
+    return current;
+  }
+}
+
+export function mergeDiff(pristine, current) {
+  if (Array.isArray(current)) {
+    return mergeDiffArray(pristine, current);
+  }
+  else if ('object' === typeof current) {
+    return mergeDiffObject(pristine, current);
+  }
+  else {
+    return mergeDiffPrimitive(pristine, current);
+  }
+}
diff --git a/packages/core/merge.js b/packages/core/merge.js
new file mode 100644
index 0000000..528aee5
--- /dev/null
+++ b/packages/core/merge.js
@@ -0,0 +1,10 @@
+import mergeWith from 'lodash.mergewith';
+
+export function merge(...args) {
+  args.push((l, r) => {
+    if (Array.isArray(l)) {
+      return r;
+    }
+  });
+  return mergeWith.apply(null, args);
+}
diff --git a/packages/core/package.json b/packages/core/package.json
index 98d4509..0996b2a 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -1,7 +1,10 @@
 {
   "name": "@avocado/core",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "main": "index.js",
   "author": "cha0s",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "lodash.mergewith": "4.6.1"
+  }
 }