147 lines
6.6 KiB
Markdown
147 lines
6.6 KiB
Markdown
# RealmJS
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Realm is a mobile database that runs directly inside phones, tablets or wearables. This repository holds the source code for Realm's JavaScript bindings for integrating with mobile apps built using ReactNative and PhoneGap.
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## Setup
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This repository uses submodules so you need to run `git submodule update --init --recursive` in the realm-js root directory before running any examples or including the project in your app.
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## ReactNative Example
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Make sure your environment is set up to run react native applications. Follow the instructions here https://facebook.github.io/react-native/docs/getting-started.html.
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The ReactNative example project is in the `examples/ReactExample` directory. You need to run `npm install` in this directory before running the example for the first time.
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## ReactNative Project Setup
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- Create a new ReactNative project `react-native init <project-name>` and open the generated XCode project.
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- Drag `RealmJS.xcodeproj` into the `Libraries` folder in your project.
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- Drag `RealmReact.framework` from the `Products` directory under `RealmJS.xcodeproj` into the `Embedded Libraries` section in the `General` tab for your app's target settings. This bundles the library with your app.
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- In the `Build Phases` tab for your app's target settings, add `RealmReact.framework` in the `Target Dependencies` and `Link Binary with Library` build phases.
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- In your app's `package.json` file, add the `realm` dependency with a path to the `realm-js/lib` folder like this: `"realm": "file:path/to/realm-js/lib"` (symlinks are not yet supported by the React Native packager, see [issue #637](https://github.com/facebook/react-native/issues/637)).
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- You can now `require('realm')` in your app's JS to use Realm!
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## Getting Started
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Start with creating a `realm` by passing it an array of `objectSchema` (object types and their properties) for each type of object it will contain:
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```js
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const Realm = require('realm');
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const personSchema = {
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name: 'Person',
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primaryKey: 'name',
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properties: [
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{name: 'name', type: Realm.Types.STRING},
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{name: 'birthday', type: Realm.Types.DATE},
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{name: 'friends', type: Realm.Types.LIST, objectType: 'Person'},
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{name: 'points', type: Realm.Types.INT, default: 0},
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],
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};
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const realm = new Realm({schema: [personSchema]});
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```
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If you'd prefer your objects inherit from a prototype, you just need to define the `schema` on the `prototype` object and instead pass in the constructor when creating a `realm`:
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```js
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function Person() {}
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Person.prototype = {
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schema: personSchema,
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get age() {
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return Math.floor((Date.now() - this.birthday.getTime()) / 31557600000);
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},
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};
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const realm = new Realm({schema: [Person]});
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```
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You can now use the `realm` instance to create new objects. When using Realm, all mutations must take place inside of a write transaction:
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```js
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realm.write(() => {
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ross = realm.create('Person', {
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name: 'Ross Geller',
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birthday: new Date(1967, 9, 18),
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friends: [chandler, joey, monica, phoebe, rachel],
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});
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});
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```
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When creating an object, values for all properties without default values need to be specified. In the example above, since the `points` property has a default property it can be ommitted.
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Changes to object properties and object deletions also need to take place in a write transactions:
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```js
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realm.write(() => {
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rachel.points++;
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rachel.friends.push(ross);
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realm.delete(janine);
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});
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```
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**Note:** If an uncaught exception occurs during a write transaction, then the write transaction will roll-back and all, deletions, and modifications will be undone.
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You can query for existing objects by passing the object type and an optional query into the `realm.objects()` method:
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```js
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let characters = realm.objects('Person');
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let chandler = realm.objects('Person', 'name = "Chandler Bing"')[0];
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```
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Queries are live updating, so as change are made to the Realm, queries are updated automatically on access.
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You can see more examples of how to use these APIs in the [ReactExample](https://github.com/realm/realm-js/tree/master/examples/ReactExample) app and in the [JS test files](https://github.com/realm/realm-js/tree/master/tests).
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## Documentation
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### `Realm` Constructor Options
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- `path` – defaults to `Realm.defaultPath` (which initially is `'Documents/default.realm'`)
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- `schema` – array of object type definitions (see below, optional if realm already created)
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- `schemaVersion` – defaults to `0` (must be incremented after changing the schema)
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### Object Types
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- `name` – string used to refer to this object type
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- `primaryKey` – optional name of `STRING` or `INT` property that should be unique
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- `properties` – array of property defitions (see below)
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### Property Types
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When definining object `properties` in a `schema`, each should have a unique `name`, and the `type` of each property must be defined as either the name of an object type in the same schema **or** as one of the following:
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- `Realm.Types.BOOL`
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- `Realm.Types.INT`
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- `Realm.Types.FLOAT`
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- `Realm.Types.DOUBLE`
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- `Realm.Types.STRING`
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- `Realm.Types.DATE`
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- `Realm.Types.DATA`
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- `Realm.Types.OBJECT` (requires `objectType`, is always `optional`)
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- `Realm.Types.LIST` (requires `objectType`, is never `optional`)
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You _may_ specify these property options as well:
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- `default` – default value when property was not specified on creation
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- `optional` – boolean indicating if this property may be assigned `null` or `undefined`
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### `Realm` Instance Methods
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#### `create(type, props [, update])`
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- `type` – string matching object `name` in the `schema` definition
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- `props` – object with property values for all required properties without a default value
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- `update` – optional boolean signaling that an existing object (matching primary key) should be updated - only the primary key property and properties which should be updated need to be specified for the `props` arguments - all missing property values will remain unchanged
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- _Returns a new realm object instance_
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#### `delete(object)`
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- `object` – realm object or array of realm objects (which can be a `List` or `Results` object)
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#### `deleteAll()`
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**WARNING:** This does what you think it does!
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#### `objects(type [, query])`
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- `type` – string matching object `name` in the `schema` definition
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- `query` – optional string that defines a query to filter results (see tests for examples)
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- _Returns `Results` object_
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#### `write(callback)`
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- `callback` – function that is synchronously called inside the write transaction
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#### `close()`
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**WARNING:** This is only for advanced use cases and generally doesn't need to be used.
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## License
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Copyright 2015 Realm Inc - All Rights Reserved
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Proprietary and Confidential
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