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

All the logic is also pretty much ported from ag.

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

Installation

npm install isbinaryfile

Usage

If you pass in one argument, this module assumes it's just the file path, and performs the appropriate file read and stat functionality internally, as sync options:

var isBinaryFile = require("isbinaryfile");

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

Ta da.

However, if you've already read and stat()-ed a file (for some other reason), you can pass in both the file's raw data and the stat's size info to save time:

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.")
  });
});

Async

Previous to version 2.0.0, this program always ran in sync mode. Now, there's an async option. Simply pass a function as your second parameter, and isBinaryFile will figure the rest out:

var isBinaryFile = require("isbinaryfile");

isBinaryFile(process.argv[2], function(err, result) {
  if (err) return console.error(err);

  if (result)
    console.log("It is!")
  else
    console.log("No.")
}

Testing

Install mocha on your machine:

npm install mocha -g

Then run npm test.

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.