add touch method for changing file timestamps

FS.common.js

@@ -470,6 +470,16 @@ var RNFS = {
     };
   },
 
+  touch(filepath: string, mtime?: Date, ctime?: Date): Promise<void> {
+    if (ctime && !(ctime instanceof Date)) throw new Error('touch: Invalid value for argument `ctime`');
+    if (mtime && !(mtime instanceof Date)) throw new Error('touch: Invalid value for argument `mtime`');
+    return RNFSManager.touch(
+      normalizeFilePath(filepath),
+      mtime && mtime.getTime(),
+      ctime && ctime.getTime()
+    );
+  },
+
   MainBundlePath: RNFSManager.RNFSMainBundlePath,
   CachesDirectoryPath: RNFSManager.RNFSCachesDirectoryPath,
   DocumentDirectoryPath: RNFSManager.RNFSDocumentDirectoryPath,

README.md

@@ -427,6 +427,10 @@ Check in the Android assets folder if the item exists. `filepath` is the relativ
 
 Reads the file at `path` and returns its checksum as determined by `algorithm`, which can be one of `md5`, `sha1`, `sha224`, `sha256`, `sha384`, `sha512`.
 
+### `touch(filepath: string, mtime?: Date, ctime?: Date): Promise<string>`
+
+Sets the modification timestamp `mtime` and creation timestamp `ctime` of the file at `filepath`. Setting `ctime` is only supported on iOS, android always sets both timestamps to `mtime`. 
+
 ### `mkdir(filepath: string, options?: MkdirOptions): Promise<void>`
 
 ```

RNFSManager.m

@@ -637,6 +637,38 @@ RCT_EXPORT_METHOD(copyAssetsFileIOS: (NSString *) imageUri
     
 }
 
+RCT_EXPORT_METHOD(touch:(NSString*)filepath
+                  mtime:(NSDate *)mtime
+                  ctime:(NSDate *)ctime
+                  resolver:(RCTPromiseResolveBlock)resolve
+                  rejecter:(RCTPromiseRejectBlock)reject)
+{
+    NSFileManager *manager = [NSFileManager defaultManager];
+    BOOL exists = [manager fileExistsAtPath:filepath isDirectory:false];
+
+    if (!exists) {
+        return reject(@"ENOENT", [NSString stringWithFormat:@"ENOENT: no such file, open '%@'", filepath], nil);
+    }
+
+    NSMutableDictionary *attr = [NSMutableDictionary dictionary];
+
+    if (mtime) {
+        [attr setValue:mtime forKey:NSFileModificationDate];
+    }
+    if (ctime) {
+        [attr setValue:ctime forKey:NSFileCreationDate];
+    }
+
+    NSError *error = nil;
+    BOOL success = [manager setAttributes:attr ofItemAtPath:filepath error:&error];
+
+    if (!success) {
+        return [self reject:reject withError:error];
+    }
+
+    resolve(nil);
+}
+
 - (NSNumber *)dateToTimeIntervalNumber:(NSDate *)date
 {
   return @([date timeIntervalSince1970]);

android/src/main/java/com/rnfs/RNFSManager.java

@@ -615,6 +615,17 @@ public class RNFSManager extends ReactContextBaseJavaModule {
     promise.resolve(info);
   }
 
+  @ReactMethod
+  public void touch(String filepath, double mtime, double ctime, Promise promise) {
+    try {
+      File file = new File(filepath);
+      promise.resolve(file.setLastModified((long) mtime));
+    } catch (Exception ex) {
+      ex.printStackTrace();
+      reject(promise, filepath, ex);
+    }
+  }
+
   private void reject(Promise promise, String filepath, Exception ex) {
     if (ex instanceof FileNotFoundException) {
       rejectFileNotFound(promise, filepath);