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isBinaryFile

Detects if a file is binary in Node.js. Similar to Perl's -B switch, in that:

  • it reads the first few thousand bytes of a file
  • checks for a null byte; if it's found, it's binary
  • flags non-ASCII characters. After a certain number of "weird" characters, the file is flagged as binary

Much of the logic is pretty much ported from ag.

Note: if the file doesn't exist, is a directory, or is empty, the function returns false.

Installation

npm install isbinaryfile

Usage

isBinaryFile(filepath, callback)

  • filepath, a string indicating the path to the file.
  • callback, a function for the callback. It has two arguments:
    • err, the typical Node.js error argument
    • result, a boolean of true or false, depending on if the file is binary

isBinaryFile(bytes, size, callback)

  • bytes, a Buffer of the file's contents.
  • size, an optional number indicating the file size.
  • callback, a function for the callback. It has two arguments:
    • err, the typical Node.js error argument
    • result, a boolean of true or false, depending on if the file is binary

isBinaryFile.sync(filepath)

  • filepath, a string indicating the path to the file.

isBinaryFile.sync(bytes, size)

  • bytes, a Buffer of the file's contents.
  • size, an number indicating the file size.

Returns a boolean of true or false, depending on if the file is binary.

Examples

var isBinaryFile = require("isbinaryfile");

fs.readFile("some_file", function(err, data) {
  fs.lstat("some_file", function(err, stat) {
    isBinaryFile(data, stat.size, function (err, result) {
      if (!err) {
        if (result) {
          console.log("It is!")
        }
        else {
          console.log("No.")
        }
      }
    });
  });
});

isBinaryFile.sync("some_file"); // true or false
var bytes = fs.readFileSync(("some_file"));
var size = fs.lstatSync(("some_file").size;
isBinaryFile.sync(bytes, size); // true or false

Testing

Run npm install to install mocha, then run npm test.