# FileSystemManager.write(Object object)

Start from base library version 2.16.1. Please remaining backward compatible.

with Promise style call: Not supported

Mini Program plugin: Support, need to Mini Program base library version no less than 2.19.2

Write file

# parameter

# Object object

attribute	type	Default values	Required	Introductions
fd	string		yes	File descriptor. fd adopt FileSystemManager.open or FileSystemManager.openSync Interface acquisition
data	string/ArrayBuffer		yes	Write content of type String or ArrayBuffer
offset	number	0	no	Only in data Type is ArrayBuffer When valid, decided arrayBuffe To be written to in the arrayBuffer Index in, default 0
length	number		no	Only in data Type is ArrayBuffer Specifies the number of bytes to write, and defaults to arrayBuffer Offset from 0 offset Number of bytes remaining after 1 byte
encoding	string	utf8	no	Only in data Type is String Specifies the character encoding to write to the file, and defaults to utf8
position	number		no	Specifies the offset at the beginning of the file, where the data will be written. when position Not passed or passed in Number Type, the data is written to the current pointer location.
success	function		no	Interface calls the successful callback function
fail	function		no	Interface calls failed callback functions
complete	function		no	Callback function at the end of an interface call (both successful and unsuccessful calls are executed)

object.encoding Legal value

value	Introductions	Minimum version
ascii
base64
binary
hex
ucs2	Read in small endorder
ucs-2	Read in small endorder
Utf16le	Read in small endorder
utf-16le	Read in small endorder
utf-8
utf8
latin1

# object.success callback

# parameter

# Object res

attribute	type	Introductions
bytesWritten	number	Number of bytes actually written to the file (note that the number of byte writes is not necessarily the same as the string characters written)

# object.fail callback

# parameter

# Object res

attribute	type	Introductions
errMsg	string	Error message

res.errMsg Legal value

value	Introductions	Minimum version
bad file descriptor	Invalid file descriptor
fail permission denied	Specified fd Path does not have write permissions
fail sdcard not mounted	android sdcard Mount failure

# sample code

const fs = wx.getFileSystemManager()
// Open the file
fs.open({
  filePath: `${wx.env.USER_DATA_PATH}/hello.txt`, 
  flag: 'a+',
  success(res) {
    // Write file
    fs.write({
      fd: res.fd,
      data: 'some text',
      success(res) {
        console.log(res.bytesWritten)
      }
    })
  }
})