data-store.md

 jsdata  
 crud
+
+
+
+```
+class Book (models.Model):
+    title = models.CharField(max_length=50)
+    authors = models.ManyToManyField(Author)
+    publisher = models.ForeignKey(Publisher, null=True, on_delete=models.SET_NULL)
+
+// JSData v3, JSDataHttpAdapter v3
+DataStore.defineMapper(name, {  // 'Book'
+  // ... endpoint, etc
+  relations: {
+    belongsTo: {
+      Publisher: {
+        foreignKey: 'publisher',
+        localField: 'publisherObj',
+      },
+    },
+    hasMany: {
+      Author: {
+        localKeys: 'authors',
+        localField: 'authorObjs',
+      }
+    },
+  },
+});
+
+DataStore.defineMapper(name, {  // 'Author'
+  // ... endpoint, etc
+  relations: {
+    hasMany: {
+      Book: {
+        foreignKeys: 'authors',
+        localField: 'books',
+      }
+    }
+  },
+});
+
+DataStore.defineMapper(name, {  // 'Publisher'
+  // ... endpoint, etc
+  // This relationship to Book is only necessary if you want Publishers to have the 'books' array (named using localField), listing all books they are related to. But 'publisherObj' can still be loaded onto a Book even without this side of the relationship defined.
+  relations: {
+    hasMany: {
+      Book: {
+        foreignKey: 'publisher',
+        localField: 'books',
+      }
+    }
+  },
+});
+
+this.Book.readList().subscribe(books => {
+
+  // loadedBooks === [
+  //   {
+  //     id: 1,
+  //     title: 'To Kill a Mockingbird',
+  //     authors: [1],
+  //     authorObjs: undefined,
+  //     publisher: 1,
+  //     publisherObj: undefined
+  //   }
+  // ]
+
+  let bookPromises = books.map((book: any) => book.loadRelations(['publisherObj', 'authorObjs']));
+  Promise.all(bookPromises).then(loadedBooks => {
+
+    // loadedBooks === [
+    //   {
+    //     id: 1,
+    //     title: 'To Kill a Mockingbird',
+    //     authors: [1],
+    //     authorObjs: [
+    //       {
+    //         id: 1,
+    //         first_name: 'Harper',
+    //         last_name: 'Lee',
+    //         books: [
+    //           {
+    //             id: 1,
+    //             title 'To Kill a Mockingbird',
+    //             authorObjs: [ { id: 1, ... } ],
+    //             ...
+    //           }
+    //         ]
+    //       }
+    //     ],
+    //     publisher: 1,
+    //     publisherObj: {
+    //       id: 1,
+    //       name: 'HarperCollins',
+    //       books: [
+    //         {
+    //           id: 1,
+    //           title: 'To Kill a Mockingbird',
+    //           publisherObj: { id: 1, ... },
+    //           ...
+    //         }
+    //       ]
+    //     }
+    //   }
+    // ]
+  });
+});
+```
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