Support for nested links

docs/linking_collections.md

@@ -80,6 +80,40 @@ Posts.addLinks({
 You created the link, and now you can use the query illustrated above. 
 We decided to choose `author` as a name for our link and `authorId` the field to store it in, but it's up to you to decide this.
 
+## Nested links
+
+Nested links are also supported:  
+
+```js
+// file: /imports/db/posts/links.js
+import Posts from '...';
+
+Posts.addLinks({
+    'authorObject.authorId': {
+        type: 'one',
+        collection: Meteor.users,
+        field: 'authorObject.authorId',
+    },
+})
+```
+
+In this example we're assuming that `authorObject` is a nested document inside `Posts` collection, and we want to link it to `Meteor.users`.  
+
+Nested arrays are also supported, e.g.:
+
+```js
+// file: /imports/db/posts/links.js
+import Posts from '...';
+
+Posts.addLinks({
+    'authorsArray.authorId': {
+        type: 'one',
+        collection: Meteor.users,
+        field: 'authorsArray.authorId',
+    },
+})
+```
+
 ## Inversed links
 
 Because we linked `Posts` with `Meteor.users` it means that we can also get all `posts` of an user.

lib/links/lib/createSearchFilters.js

@@ -26,12 +26,29 @@ export default function createSearchFilters(object, linker, metaFilters) {
     }
 }
 
+function getIdQueryFieldStorage(object, fieldStorage, isMany = false) {
+    const [root, ...rest] = fieldStorage.split('.');
+    if (rest.length === 0) {
+        const ids = object[fieldStorage];
+        return _.isArray(ids) ? {$in: ids} : ids;
+    }
+
+    const nestedPath = rest.join('.');
+    const rootValue = object[root];
+    if (_.isArray(rootValue)) {
+        return {$in: _.uniq(_.union(...rootValue.map(item => dot.pick(nestedPath, item))))};
+    }
+    else if (_.isObject(rootValue)) {
+        return isMany ? {$in: dot.pick(nestedPath, rootValue) || []} : dot.pick(nestedPath, rootValue);
+    }
+}
+
 export function createOne(object, linker) {
     return {
         // Using {$in: []} as a workaround because foreignIdentityField which is not _id is not required to be set
         // and {something: undefined} in query returns all the records.
         // $in: [] ensures that nothing will be returned for this query
-        [linker.foreignIdentityField]: dot.pick(linker.linkStorageField, object) || {$in: []},
+        [linker.foreignIdentityField]: getIdQueryFieldStorage(object, linker.linkStorageField) || {$in: []},
     };
 }
 
@@ -69,19 +86,8 @@ export function createOneMetaVirtual(object, fieldStorage, metaFilters) {
 }
 
 export function createMany(object, linker) {
-    const [root, ...nested] = linker.linkStorageField.split('.');
-    if (nested.length > 0) {
-        const arr = object[root];
-        const ids = arr ? _.uniq(_.union(arr.map(obj => _.isObject(obj) ? dot.pick(nested.join('.'), obj) : []))) : [];
-        return {
-            [linker.foreignIdentityField]: {$in: ids}
-        };
-    }
-    const value = object[linker.linkStorageField];
     return {
-        [linker.foreignIdentityField]: {
-            $in: _.isArray(value) ? value : (value ? [value] : []),
-        }
+        [linker.foreignIdentityField]: getIdQueryFieldStorage(object, linker.linkStorageField, true) || {$in: []},
     };
 }
 

lib/query/hypernova/aggregateSearchFilters.js

@@ -1,8 +1,24 @@
 import sift from 'sift';
 import dot from 'dot-object';
 
+function getIdsFromObject(object, field) {
+    const parts = field.split('.');
+    if (parts.length === 1) {
+        return [dot.pick(field, object)];
+    }
+
+    const rootValue = object[parts[0]];
+    if (_.isArray(rootValue)) {
+        return rootValue.map(item => dot.pick(parts.slice(1).join('.'), item));
+    }
+    else if (_.isObject(rootValue)) {
+        return [dot.pick(parts.slice(1).join('.'), rootValue)];
+    }
+    return [];
+}
+
 function extractIdsFromArray(array, field) {
-    return (array || []).map(obj => _.isObject(obj) ? dot.pick(field, obj) : undefined).filter(v => !!v);
+    return _.flatten((array || []).map(obj => _.isObject(obj) ? getIdsFromObject(obj, field) : [])).filter(v => !!v);
 }
 
 /**
@@ -44,7 +60,7 @@ export default class AggregateFilters {
     createOne() {
         if (!this.isVirtual) {
             return {
-                _id: {
+                [this.foreignIdentityField]: {
                     $in: _.uniq(extractIdsFromArray(this.parentObjects, this.linkStorageField))
                 }
             };