Introduce RCTCallableJSModules

Summary:
This is a Bridgeless-compatible API to allow our NativeModules to call JSModule methods.

Changelog: [iOS][Added] - Introduce RCTCallableJSModules API for NativeModules

Differential Revision: D28395448

fbshipit-source-id: b7929ba8b4cc4410361961b45efa23c76baacd24

Author: RSNara

React/Base/RCTBridgeModule.h

@@ -15,6 +15,7 @@
 @class RCTModuleRegistry;
 @class RCTViewRegistry;
 @class RCTBundleManager;
+@class RCTCallableJSModules;
 
 /**
  * The type of a block that is capable of sending a response to a bridged
@@ -146,6 +147,17 @@ RCT_EXTERN_C_END
  */
 @property (nonatomic, weak, readwrite) RCTBundleManager *bundleManager;
 
+/**
+ * A reference to an RCTCallableJSModules. Useful for modules that need to
+ * call into methods on JavaScript modules registered as callable with
+ * React Native.
+ *
+ * To implement this in your module, just add `@synthesize callableJSModules =
+ * _callableJSModules;`. If using Swift, add `@objc var callableJSModules:
+ * RCTCallableJSModules!` to your module.
+ */
+@property (nonatomic, weak, readwrite) RCTCallableJSModules *callableJSModules;
+
 /**
  * A reference to the RCTBridge. Useful for modules that require access
  * to bridge features, such as sending events or making JS calls. This
@@ -443,3 +455,24 @@ typedef UIView * (^RCTBridgelessComponentViewProvider)(NSNumber *);
 
 - (UIView *)viewForReactTag:(NSNumber *)reactTag;
 @end
+
+typedef void (^RCTBridgelessJSModuleMethodInvoker)(
+    NSString *moduleName,
+    NSString *methodName,
+    NSArray *args,
+    dispatch_block_t onComplete);
+
+/**
+ * A class that allows NativeModules to call methods on JavaScript modules registered
+ * as callable with React Native.
+ */
+@interface RCTCallableJSModules : NSObject
+- (void)setBridge:(RCTBridge *)bridge;
+- (void)setBridgelessJSModuleMethodInvoker:(RCTBridgelessJSModuleMethodInvoker)bridgelessJSModuleMethodInvoker;
+
+- (void)invokeModule:(NSString *)moduleName method:(NSString *)methodName withArgs:(NSArray *)args;
+- (void)invokeModule:(NSString *)moduleName
+              method:(NSString *)methodName
+            withArgs:(NSArray *)args
+          onComplete:(dispatch_block_t)onComplete;
+@end

React/Base/RCTCallableJSModules.m

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTBridge.h"
+#import "RCTBridgeModule.h"
+
+@implementation RCTCallableJSModules {
+  RCTBridgelessJSModuleMethodInvoker _bridgelessJSModuleMethodInvoker;
+  __weak RCTBridge *_bridge;
+}
+
+- (void)setBridge:(RCTBridge *)bridge
+{
+  _bridge = bridge;
+}
+
+- (void)setBridgelessJSModuleMethodInvoker:(RCTBridgelessJSModuleMethodInvoker)bridgelessJSModuleMethodInvoker
+{
+  _bridgelessJSModuleMethodInvoker = bridgelessJSModuleMethodInvoker;
+}
+
+- (void)invokeModule:(NSString *)moduleName method:(NSString *)methodName withArgs:(NSArray *)args
+{
+  [self invokeModule:moduleName method:methodName withArgs:args onComplete:NULL];
+}
+
+- (void)invokeModule:(NSString *)moduleName
+              method:(NSString *)methodName
+            withArgs:(NSArray *)args
+          onComplete:(dispatch_block_t)onComplete
+{
+  RCTBridge *bridge = _bridge;
+  if (bridge) {
+    [bridge enqueueJSCall:moduleName method:methodName args:args completion:onComplete];
+    return;
+  }
+
+  if (_bridgelessJSModuleMethodInvoker) {
+    _bridgelessJSModuleMethodInvoker(moduleName, methodName, args, onComplete);
+  }
+}
+
+@end