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FileSystemFileEntry: createWriter() method

files/en-us/web/api/filesystemfileentry/createwriter/index.md

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{{APIRef("File and Directories Entries API")}}{{deprecated_header}}{{Non-standard_header}}

The {{domxref("FileSystemFileEntry")}} interface's method createWriter() returns a {{domxref("FileWriter")}} object which can be used to write data into the file represented by the directory entry.

Syntax

js-nolint
createWriter(successCallback)
createWriter(successCallback, errorCallback)

Parameters

  • successCallback
    • : A callback function which is called when the {{domxref("FileWriter")}} has been created successfully; the FileWriter is passed into the callback as the only parameter.
  • errorCallback {{optional_inline}}
    • : If provided, this must be a method which is called when an error occurs while trying to create the {{domxref("FileWriter")}}. This callback receives as input a {{domxref("DOMException")}} object describing the error.

Return value

None ({{jsxref("undefined")}}).

Examples

This example establishes a method, writeToFileEntry(), which outputs a text string to the file corresponding to the passed-in directory entry.

js
function writeToFileEntry(entry, text) {
  entry.createWriter(
    (fileWriter) => {
      let data = Blob([text], { type: "text/plain" });

      fileWriter.write(data);
    },
    (error) => {
      /* do whatever to handle the error */
    },
  );
}

The success callback for the createWriter() call takes the text which was passed in and creates a new {{domxref("Blob")}} object of type text/plain that contains the passed text. This blob is then output to the {{domxref("FileWriter")}} object to be written to the file.

Specifications

This feature is not part of any specification anymore. It is no longer on track to become a standard.

Browser compatibility

{{Compat}}

See also