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Merge pull request #801 from brentvatne/fix-bridge-docs
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Fix bridge docs for `RCT_EXPORT`
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frantic committed Apr 10, 2015
2 parents 4d0e494 + b0d2c3b commit 3d602de
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9 changes: 6 additions & 3 deletions README.md
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Expand Up @@ -119,7 +119,7 @@ var GeoInfo = React.createClass({

## Extensibility

It is certainly possible to create a great app using React Native without writing a single line of native code, but React Native is also designed to be easily extended with custom native views and modules - that means you can reuse anything you've already built, and can import and use your favorite native libraries. To create a simple module in iOS, create a new class that implements the `RCTBridgeModule` protocol, and add `RCT_EXPORT` to the function you want to make available in JavaScript.
It is certainly possible to create a great app using React Native without writing a single line of native code, but React Native is also designed to be easily extended with custom native views and modules - that means you can reuse anything you've already built, and can import and use your favorite native libraries. To create a simple module in iOS, create a new class that implements the `RCTBridgeModule` protocol, and wrap the function that you want to make available to JavaScript in `RCT_EXPORT_METHOD`. Additionally, the class itself must be explicitly exported with `RCT_EXPORT_MODULE();`.

```objc
// Objective-C
Expand All @@ -130,9 +130,12 @@ It is certainly possible to create a great app using React Native without writin
@end

@implementation MyCustomModule
- (void)processString:(NSString *)input callback:(RCTResponseSenderBlock)callback

RCT_EXPORT_MODULE();

// Available as NativeModules.MyCustomModule.processString
RCT_EXPORT_METHOD(processString:(NSString *)input callback:(RCTResponseSenderBlock)callback)
{
RCT_EXPORT(); // available as NativeModules.MyCustomModule.processString
callback(@[[input stringByReplacingOccurrencesOfString:@"Goodbye" withString:@"Hello"]]);
}
@end
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25 changes: 10 additions & 15 deletions docs/NativeModulesIOS.md
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Expand Up @@ -28,15 +28,16 @@ Native module is just an Objectve-C class that implements `RCTBridgeModule` prot
@end
```

React Native will not expose any methods of `CalendarManager` to JavaScript unless explicitly asked. Fortunately this is pretty easy with `RCT_EXPORT`:
React Native will not expose any methods of `CalendarManager` to JavaScript unless explicitly asked. Fortunately this is pretty easy with `RCT_EXPORT_METHOD`:

```objective-c
// CalendarManager.m
@implementation CalendarManager

- (void)addEventWithName:(NSString *)name location:(NSString *)location
RCT_EXPORT_MODULE();

RCT_EXPORT_METHOD(addEvent:(NSString *)name location:(NSString *)location)
{
RCT_EXPORT();
RCTLogInfo(@"Pretending to create an event %@ at %@", name, location);
}

Expand All @@ -47,12 +48,10 @@ Now from your JavaScript file you can call the method like this:

```javascript
var CalendarManager = require('NativeModules').CalendarManager;
CalendarManager.addEventWithName('Birthday Party', '4 Privet Drive, Surrey');
CalendarManager.addEvent('Birthday Party', '4 Privet Drive, Surrey');
```

Notice that the exported method name was generated from first part of Objective-C selector. Sometimes it results in a non-idiomatic JavaScript name (like the one in our example). You can change the name by supplying an optional argument to `RCT_EXPORT`, e.g. `RCT_EXPORT(addEvent)`.

The return type of the method should always be `void`. React Native bridge is asynchronous, so the only way to pass a result to JavaScript is by using callbacks or emitting events (see below).
The return type of bridge methods is always `void`. React Native bridge is asynchronous, so the only way to pass a result to JavaScript is by using callbacks or emitting events (see below).

## Argument types

Expand All @@ -68,9 +67,8 @@ React Native supports several types of arguments that can be passed from JavaScr
In our `CalendarManager` example, if we want to pass event date to native, we have to convert it to a string or a number:

```objective-c
- (void)addEventWithName:(NSString *)name location:(NSString *)location date:(NSInteger)secondsSinceUnixEpoch
RCT_EXPORT_METHOD(addEvent:(NSString *)name location:(NSString *)location date:(NSInteger)secondsSinceUnixEpoch)
{
RCT_EXPORT(addEvent);
NSDate *date = [NSDate dateWithTimeIntervalSince1970:secondsSinceUnixEpoch];
}
```
Expand All @@ -80,9 +78,8 @@ As `CalendarManager.addEvent` method gets more and more complex, the number of a
```objective-c
#import "RCTConvert.h"
- (void)addEventWithName:(NSString *)name details:(NSDictionary *)details
RCT_EXPORT_METHOD(addEvent:(NSString *)name details:(NSDictionary *)details)
{
RCT_EXPORT(addEvent);
NSString *location = [RCTConvert NSString:details[@"location"]]; // ensure location is a string
...
}
Expand Down Expand Up @@ -112,9 +109,8 @@ CalendarManager.addEvent('Birthday Party', {
Native module also supports a special kind of argument- a callback. In most cases it is used to provide the function call result to JavaScript.

```objective-c
- (void)findEvents:(RCTResponseSenderBlock)callback
RCT_EXPORT_METHOD(findEvents:(RCTResponseSenderBlock)callback)
{
RCT_EXPORT();
NSArray *events = ...
callback(@[[NSNull null], events]);
}
Expand Down Expand Up @@ -142,9 +138,8 @@ The native module should not have any assumptions about what thread it is being


```objective-c
- (void)addEventWithName:(NSString *)name callback:(RCTResponseSenderBlock)callback
RCT_EXPORT_METHOD(addEvent:(NSString *)name callback:(RCTResponseSenderBlock)callback)
{
RCT_EXPORT(addEvent);
dispatch_async(dispatch_get_main_queue(), ^{
// Call iOS API on main thread
...
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8 changes: 5 additions & 3 deletions website/src/react-native/index.js
Original file line number Diff line number Diff line change
Expand Up @@ -159,7 +159,7 @@ var GeoInfo = React.createClass({

<h2>Extensibility</h2>
<p>
It is certainly possible to create a great app using React Native without writing a single line of native code, but React Native is also designed to be easily extended with custom native views and modules - that means you can reuse anything you{"'"}ve already built, and can import and use your favorite native libraries. To create a simple module in iOS, create a new class that implements the RCTBridgeModule protocol, and add RCT_EXPORT to the function you want to make available in JavaScript.
It is certainly possible to create a great app using React Native without writing a single line of native code, but React Native is also designed to be easily extended with custom native views and modules - that means you can reuse anything you{"'"}ve already built, and can import and use your favorite native libraries. To create a simple module in iOS, create a new class that implements the RCTBridgeModule protocol, and wrap the function that you want to make available to JavaScript in RCT_EXPORT_METHOD. Additionally, the class itself must be explicitly exported with RCT_EXPORT_MODULE();.
</p>
<Prism>
{`// Objective-C
Expand All @@ -171,9 +171,11 @@ var GeoInfo = React.createClass({
@implementation MyCustomModule
- (void)processString:(NSString *)input callback:(RCTResponseSenderBlock)callback
RCT_EXPORT_MODULE();
// Available as NativeModules.MyCustomModule.processString
RCT_EXPORT_METHOD(processString:(NSString *)input callback:(RCTResponseSenderBlock)callback)
{
RCT_EXPORT(); // available as NativeModules.MyCustomModule.processString
callback(@[[input stringByReplacingOccurrencesOfString:@"Goodbye" withString:@"Hello"];]]);
}
@end`}
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