Merge pull request #175 from Expensify/ionatan_changesmergewith

Address comments from review regarding mergeWith changes

Author: Justice Arthur

README.md

@@ -63,7 +63,7 @@ The data will then be cached and stored via [`AsyncStorage`](https://github.com/
 
 We can also use `Onyx.merge()` to merge new `Object` or `Array` data in with existing data.
 
-For `Array` the default behavior is to concatenate replace it fully, effectively making it equivalent to set:
+For `Array` the default behavior is to replace it fully, effectively making it equivalent to set:
 
 ```javascript
 Onyx.merge(ONYXKEYS.EMPLOYEE_LIST, ['Joe']); // -> ['Joe']
@@ -77,7 +77,7 @@ Onyx.merge(ONYXKEYS.POLICY, {id: 1}); // -> {id: 1}
 Onyx.merge(ONYXKEYS.POLICY, {name: 'My Workspace'}); // -> {id: 1, name: 'My Workspace'}
 ```
 
-Arrays inside objects will NOT be concatenated and instead will be replaced fully, same as arrays not inside objects:
+Arrays inside objects will be replaced fully, same as arrays not inside objects:
 
 ```javascript
 Onyx.merge(ONYXKEYS.POLICY, {employeeList: ['Joe', 'Jack']}); // -> {employeeList: ['Joe', 'Jack']}

lib/Onyx.js

@@ -1,13 +1,12 @@
 import _ from 'underscore';
 import Str from 'expensify-common/lib/str';
 import lodashMerge from 'lodash/merge';
-import lodashMergeWith from 'lodash/mergeWith';
 import lodashGet from 'lodash/get';
 import Storage from './storage';
 import * as Logger from './Logger';
 import cache from './OnyxCache';
 import createDeferredTask from './createDeferredTask';
-import customizerForMergeWith from './customizerForMergeWith';
+import mergeWithCustomized from './mergeWithCustomized';
 
 // Keeps track of the last connectionID that was used so we can keep incrementing it
 let lastConnectionID = 0;
@@ -663,7 +662,7 @@ function applyMerge(key, data) {
     if (_.isObject(data) || _.every(mergeValues, _.isObject)) {
         // Object values are merged one after the other
         return _.reduce(mergeValues, (modifiedData, mergeValue) => {
-            const newData = lodashMergeWith({}, modifiedData, mergeValue, customizerForMergeWith);
+            const newData = mergeWithCustomized({}, modifiedData, mergeValue);
 
             // We will also delete any object keys that are undefined or null.
             // Deleting keys is not supported by AsyncStorage so we do it this way.
@@ -734,7 +733,7 @@ function initializeWithDefaultKeyStates() {
         .then((pairs) => {
             const asObject = _.object(pairs);
 
-            const merged = lodashMergeWith(asObject, defaultKeyStates, customizerForMergeWith);
+            const merged = mergeWithCustomized(asObject, defaultKeyStates);
             cache.merge(merged);
             _.each(merged, (val, key) => keyChanged(key, val));
         });

lib/OnyxCache.js

@@ -1,6 +1,5 @@
 import _ from 'underscore';
-import lodashMergeWith from 'lodash/mergeWith';
-import customizerForMergeWith from './customizerForMergeWith';
+import mergeWithCustomized from './mergeWithCustomized';
 
 const isDefined = _.negate(_.isUndefined);
 
@@ -111,7 +110,7 @@ class OnyxCache {
      * @param {Record<string, *>} data - a map of (cache) key - values
      */
     merge(data) {
-        this.storageMap = lodashMergeWith({}, this.storageMap, data, customizerForMergeWith);
+        this.storageMap = mergeWithCustomized({}, this.storageMap, data);
 
         const storageKeys = this.getAllKeys();
         const mergedKeys = _.keys(data);

lib/customizerForMergeWith.js lib/mergeWithCustomized.jslib/customizerForMergeWith.js renamed to lib/mergeWithCustomized.js

@@ -1,4 +1,4 @@
-import _ from 'underscore';
+import lodashMergeWith from 'lodash/mergeWith';
 
 /**
  * When merging 2 objects into onyx that contain an array, we want to completely replace the array instead of the default
@@ -13,9 +13,14 @@ import _ from 'underscore';
  */
 // eslint-disable-next-line rulesdir/prefer-early-return
 function customizerForMergeWith(objValue, srcValue) {
-    if (_.isArray(objValue)) {
+    // eslint-disable-next-line rulesdir/prefer-underscore-method
+    if (Array.isArray(objValue)) {
         return srcValue;
     }
 }
 
-export default customizerForMergeWith;
+function mergeWithCustomized(...args) {
+    return lodashMergeWith(...args, customizerForMergeWith);
+}
+
+export default mergeWithCustomized;

lib/storage/providers/LocalForage.js

@@ -6,9 +6,8 @@
 
 import localforage from 'localforage';
 import _ from 'underscore';
-import lodashMergeWith from 'lodash/mergeWith';
 import SyncQueue from '../../SyncQueue';
-import customizerForMergeWith from '../../customizerForMergeWith';
+import mergeWithCustomized from '../../mergeWithCustomized';
 
 localforage.config({
     name: 'OnyxDB',
@@ -25,7 +24,7 @@ const provider = {
             return localforage.getItem(key)
                 .then((existingValue) => {
                     const newValue = _.isObject(existingValue)
-                        ? lodashMergeWith({}, existingValue, value, customizerForMergeWith)
+                        ? mergeWithCustomized({}, existingValue, value)
                         : value;
                     return localforage.setItem(key, newValue);
                 });