Remove null values in nested objects

lib/Onyx.d.ts

@@ -202,7 +202,7 @@ declare function multiSet(data: Partial<NullableKeyValueMapping>): Promise<void>
  * @param key ONYXKEYS key
  * @param value Object or Array value to merge
  */
-declare function merge<TKey extends OnyxKey>(key: TKey, value: NullableProperties<PartialDeep<KeyValueMapping[TKey]>>): Promise<void>;
+declare function merge<TKey extends OnyxKey>(key: TKey, value: NullishDeep<KeyValueMapping[TKey]>): Promise<void>;
 
 /**
  * Clear out all the data in the store

lib/Onyx.js

@@ -1020,7 +1020,13 @@ function set(key, value) {
         Logger.logAlert(`Onyx.set() called after Onyx.merge() for key: ${key}. It is recommended to use set() or merge() not both.`);
     }
 
-    const valueWithNullRemoved = utils.removeNullObjectValues(value);
+    // In case value is an object we want to remove all null values
+    // utils.fastMerge recursively goes through the object and removes all null values
+    // Passing two identical objects as source and target to fastMerge will not change it, but only remove the null values
+    let valueWithNullRemoved = value;
+    if (typeof value === 'object' && !_.isArray(value)) {
+        valueWithNullRemoved = utils.fastMerge(value, value);
+    }
 
     const hasChanged = cache.hasValueChanged(key, valueWithNullRemoved);
 
@@ -1077,9 +1083,10 @@ function multiSet(data) {
  * @private
  * @param {*} existingValue
  * @param {Array<*>} changes Array of changes that should be applied to the existing value
+ * @param {Boolean} shouldRemoveNullObjectValues
  * @returns {*}
  */
-function applyMerge(existingValue, changes) {
+function applyMerge(existingValue, changes, shouldRemoveNullObjectValues = true) {
     const lastChange = _.last(changes);
 
     if (_.isArray(existingValue) || _.isArray(lastChange)) {
@@ -1090,7 +1097,7 @@ function applyMerge(existingValue, changes) {
         // Object values are merged one after the other
         // lodash adds a small overhead so we don't use it here
         // eslint-disable-next-line prefer-object-spread, rulesdir/prefer-underscore-method
-        return _.reduce(changes, (modifiedData, change) => utils.fastMerge(modifiedData, change),
+        return _.reduce(changes, (modifiedData, change) => utils.fastMerge(modifiedData, change, shouldRemoveNullObjectValues),
             existingValue || {});
     }
 
@@ -1132,21 +1139,21 @@ function merge(key, changes) {
         .then((existingValue) => {
             try {
                 // We first only merge the changes, so we can provide these to the native implementation (SQLite uses only delta changes in "JSON_PATCH" to merge)
-                let batchedChanges = applyMerge(undefined, mergeQueue[key]);
+                let batchedChanges = applyMerge(undefined, mergeQueue[key], false);
 
                 // Clean up the write queue, so we don't apply these changes again
                 delete mergeQueue[key];
                 delete mergeQueuePromise[key];
 
                 // After that we merge the batched changes with the existing value
-                const modifiedData = utils.removeNullObjectValues(applyMerge(existingValue, [batchedChanges]));
+                const modifiedData = applyMerge(existingValue, [batchedChanges]);
 
                 // On native platforms we use SQLite which utilises JSON_PATCH to merge changes.
                 // JSON_PATCH generally removes top-level nullish values from the stored object.
-                // When there is no existing value though, SQLite will just insert the changes as a new value and thus the top-level nullish values won't be removed.
-                // Therefore we need to remove nullish values from the `batchedChanges` which are sent to the SQLite, if no existing value is present.
+                // When there is no existing value though, SQLite will just insert the changes as a new value and thus the null values won't be removed.
+                // Therefore we need to remove null values from the `batchedChanges` which are sent to the SQLite, if no existing value is present.
                 if (!existingValue) {
-                    batchedChanges = utils.removeNullObjectValues(batchedChanges);
+                    batchedChanges = applyMerge(undefined, mergeQueue[key], true);
                 }
 
                 const hasChanged = cache.hasValueChanged(key, modifiedData);

lib/storage/providers/IDBKeyVal.js

@@ -56,7 +56,7 @@ const provider = {
             const upsertMany = _.map(pairs, ([key, value], index) => {
                 const prev = values[index];
                 const newValue = _.isObject(prev) ? utils.fastMerge(prev, value) : value;
-                return promisifyRequest(store.put(utils.removeNullObjectValues(newValue), key));
+                return promisifyRequest(store.put(newValue, key));
             });
             return Promise.all(upsertMany);
         });

lib/types.d.ts

@@ -1,10 +1,13 @@
 import {Merge} from 'type-fest';
+import {BuiltIns} from 'type-fest/source/internal';
 
 /**
  * Represents a deeply nested record. It maps keys to values,
  * and those values can either be of type `TValue` or further nested `DeepRecord` instances.
  */
-type DeepRecord<TKey extends string | number | symbol, TValue> = {[key: string]: TValue | DeepRecord<TKey, TValue>};
+type DeepRecord<TKey extends string | number | symbol, TValue> = {
+    [key: string]: TValue | DeepRecord<TKey, TValue>;
+};
 
 /**
  * Represents type options to configure all Onyx methods.
@@ -180,26 +183,42 @@ type OnyxEntry<TOnyxValue> = TOnyxValue | null;
  */
 type OnyxCollection<TOnyxValue> = OnyxEntry<Record<string, TOnyxValue | null>>;
 
+type NonTransformableTypes =
+    | BuiltIns
+    | ((...args: any[]) => unknown)
+    | Map<unknown, unknown>
+    | Set<unknown>
+    | ReadonlyMap<unknown, unknown>
+    | ReadonlySet<unknown>
+    | unknown[]
+    | readonly unknown[];
+
 /**
- * The `NullableProperties<T>` sets the values of all properties in `T` to be nullable (i.e., `| null`).
- * It doesn't recurse into nested property values, this means it applies the nullability only to the top-level properties.
+ * Create a type from another type with all keys and nested keys set to optional or null.
+ *
+ * @example
+ * const settings: Settings = {
+ *	 textEditor: {
+ *	 	fontSize: 14;
+ *	 	fontColor: '#000000';
+ *	 	fontWeight: 400;
+ *	 }
+ *	 autosave: true;
+ * };
  *
- * @template T The type of the properties to convert to nullable properties.
+ * const applySavedSettings = (savedSettings: NullishDeep<Settings>) => {
+ * 	 return {...settings, ...savedSettings};
+ * }
+ *
+ * settings = applySavedSettings({textEditor: {fontWeight: 500, fontColor: null}});
  */
-type NullableProperties<T> = {
-    [P in keyof T]: T[P] | null;
-};
+type NullishDeep<T> = T extends NonTransformableTypes ? T : T extends object ? NullishObjectDeep<T> : unknown;
 
-export {
-    CollectionKey,
-    CollectionKeyBase,
-    CustomTypeOptions,
-    DeepRecord,
-    Key,
-    KeyValueMapping,
-    OnyxCollection,
-    OnyxEntry,
-    OnyxKey,
-    Selector,
-    NullableProperties,
+/**
+Same as `NullishDeep`, but accepts only `object`s as inputs. Internal helper for `NullishDeep`.
+*/
+type NullishObjectDeep<ObjectType extends object> = {
+    [KeyType in keyof ObjectType]?: NullishDeep<ObjectType[KeyType]> | null;
 };
+
+export {CollectionKey, CollectionKeyBase, CustomTypeOptions, DeepRecord, Key, KeyValueMapping, OnyxCollection, OnyxEntry, OnyxKey, Selector, NullishDeep};

lib/utils.js

@@ -25,16 +25,24 @@ function isMergeableObject(val) {
 /**
 * @param {Object} target
 * @param {Object} source
+* @param {Boolean} shouldRemoveNullObjectValues
 * @returns {Object}
 */
-function mergeObject(target, source) {
+function mergeObject(target, source, shouldRemoveNullObjectValues = true) {
+    const targetAndSourceIdentical = target === source;
+
     const destination = {};
     if (isMergeableObject(target)) {
         // lodash adds a small overhead so we don't use it here
         // eslint-disable-next-line rulesdir/prefer-underscore-method
         const targetKeys = Object.keys(target);
         for (let i = 0; i < targetKeys.length; ++i) {
             const key = targetKeys[i];
+
+            // If shouldRemoveNullObjectValues is true, we want to remove null values from the merged object
+            // eslint-disable-next-line no-continue
+            if (shouldRemoveNullObjectValues && (target[key] == null || source[key] === null)) { continue; }
+
             destination[key] = target[key];
         }
     }
@@ -44,54 +52,44 @@ function mergeObject(target, source) {
     const sourceKeys = Object.keys(source);
     for (let i = 0; i < sourceKeys.length; ++i) {
         const key = sourceKeys[i];
-        if (source[key] === undefined) {
-            // eslint-disable-next-line no-continue
-            continue;
-        }
+
+        // If shouldRemoveNullObjectValues is true, we want to remove null values from the merged object
+        // eslint-disable-next-line no-continue
+        if (source[key] === undefined || (shouldRemoveNullObjectValues && source[key] === null)) { continue; }
+
         if (!isMergeableObject(source[key]) || !target[key]) {
+            // eslint-disable-next-line no-continue
+            if (targetAndSourceIdentical) { continue; }
             destination[key] = source[key];
         } else {
             // eslint-disable-next-line no-use-before-define
-            destination[key] = fastMerge(target[key], source[key]);
+            destination[key] = fastMerge(target[key], source[key], shouldRemoveNullObjectValues);
         }
     }
 
     return destination;
 }
 
 /**
+ * Merges two objects and removes null values if "shouldRemoveNullObjectValues" is set to true
+ *
+ * We generally want to remove null values from objects written to disk and cache, because it decreases the amount of data stored in memory and on disk.
+ * On native, when merging an existing value with new changes, SQLite will use JSON_PATCH, which removes top-level nullish values.
+ * To be consistent with the behaviour for merge, we'll also want to remove null values for "set" operations.
+ *
 * @param {Object|Array} target
 * @param {Object|Array} source
+* @param {Boolean} shouldRemoveNullObjectValues
 * @returns {Object|Array}
 */
-function fastMerge(target, source) {
+function fastMerge(target, source, shouldRemoveNullObjectValues = true) {
     // lodash adds a small overhead so we don't use it here
     // eslint-disable-next-line rulesdir/prefer-underscore-method
     if (_.isArray(source) || _.isNull(source) || _.isUndefined(source)) {
         return source;
     }
-    return mergeObject(target, source);
-}
-
-/**
- * We generally want to remove top-level nullish values from objects written to disk and cache, because it decreases the amount of data stored in memory and on disk.
- * On native, when merging an existing value with new changes, SQLite will use  JSON_PATCH, which removes top-level nullish values.
- * To be consistent with the behaviour for merge, we'll also want to remove nullish values for "set" operations.
- * On web, IndexedDB will keep the top-level keys along with a null value and this uses up storage and memory.
- * This method will ensure that keys for null values are removed before an object is written to disk and cache so that all platforms are storing the data in the same efficient way.
- * @private
- * @param {*} value
- * @returns {*}
- */
-function removeNullObjectValues(value) {
-    if (_.isArray(value) || !_.isObject(value)) {
-        return value;
-    }
-
-    const objectWithoutNullObjectValues = _.omit(value, objectValue => _.isNull(objectValue));
-
-    return objectWithoutNullObjectValues;
+    return mergeObject(target, source, shouldRemoveNullObjectValues);
 }
 
-export default {removeNullObjectValues, areObjectsEmpty, fastMerge};
+export default {areObjectsEmpty, fastMerge};
 

tests/unit/onyxTest.js

@@ -223,7 +223,7 @@ describe('Onyx', () => {
             });
     });
 
-    it('should remove top-level keys that are set to null/undefined when merging', () => {
+    it('should remove keys that are set to null when merging', () => {
         let testKeyValue;
 
         connectionID = Onyx.connect({
@@ -234,13 +234,31 @@ describe('Onyx', () => {
             },
         });
 
-        return Onyx.set(ONYX_KEYS.TEST_KEY, {test1: 'test1', test2: 'test2'})
+        return Onyx.set(ONYX_KEYS.TEST_KEY, {
+            test1: {
+                test2: 'test2',
+                test3: 'test3',
+            },
+        })
             .then(() => {
-                expect(testKeyValue).toEqual({test1: 'test1', test2: 'test2'});
+                expect(testKeyValue).toEqual({
+                    test1: {
+                        test2: 'test2',
+                        test3: 'test3',
+                    },
+                });
+                return Onyx.merge(ONYX_KEYS.TEST_KEY, {
+                    test1: {
+                        test2: null,
+                    },
+                });
+            })
+            .then(() => {
+                expect(testKeyValue).toEqual({test1: {test3: 'test3'}});
                 return Onyx.merge(ONYX_KEYS.TEST_KEY, {test1: null});
             })
             .then(() => {
-                expect(testKeyValue).toEqual({test2: 'test2'});
+                expect(testKeyValue).toEqual({});
             });
     });