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, an number indicating the size of the file.
• 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, an number indicating the size of the file.
• 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");

if (isBinaryFile(process.argv[2]))
  console.log("It is!")
else
  console.log("No.")

fs.readFile(process.argv[2], function(err, data) {
  fs.lstat(process.argv[2], function(err, stat) {
    if (isBinaryFile(data, stat.size))
      console.log("It is!")
    else
      console.log("No.")
  });
});

isBinaryFile.sync(process.argv[2]); // true or false
var stat = fs.lstatSync(process.argv[2]);
isBinaryFile.sync(process.argv[2], stat.size); // true or false

Testing

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