Writing and Reading from a File System for TIzen

Create a File:

Creates a empty new file in a specified location that is relative to the directory.
"File createFile(DOMString relativeFilePath);"

Example:
tizen.filesystem.resolve(
     <absolute path>, 
    function(dir){
     dir.createFile(<filename>);
    }, function(e) {
      console.log("Error" + e.message);
    }, "rw"
);



Writing to a File:

Writes the specified DOMString to a FileStream.
"void write(DOMString stringData);"

Example:
tizen.filesystem.resolve(

<filename with absolute path>, 

function(fd){

  var filehandler=fd;

    fd.openStream(
            "w",
            function(fs){
              fs.write(<data>);
              fs.close();
            }, function(e) {
                console.log("Error " + e.message);
            }, "UTF-8"
        );      
    }, function(e)  {
      console.log("Error" + e.message);
    }, "w"
);



Reading From a File:

Reads the specified number of characters from the position of the file pointer in a FileStream and returns the characters as a string. The resulting string length might be shorter than charCount if EOF is true.
"DOMString read(long charCount);"


Example:
tizen.filesystem.resolve(
     <filename with absolute path>
    function(fd){
    var filehandler=fd;
    fd.openStream(
            "r",
            function(fs){
             var data = fs.read(filehandler.fileSize);
            fs.close();
            }, function(e) {
              console.log("Error " + e.message);
            }, "UTF-8"
        );      
    }, function(e)  {
      console.log("Error" + e.message);
    }, "r"
);

For all the above operations Privilege has to be set in the config file:
Go to Config File > Privilege > and ADD the following privileges
http://tizen.org/privilege/filesystem.read and
http://tizen.org/privilege/filesystem.write

For more info please refer to: FileSystem API