Scanfs NPM | npm.io

scanfs

A small library that does a breadth-first walk of the filesystem, and emits (customizable) events on the way.

install

npm i --save scanfs

example

A example showing syntax (helper functions not shown):

// instantiate with ignore patterns and a custom event function
var Scanfs = require('scanfs'),
    scan = new Scanfs([/\/node_modules$/, '.git'], customEvents);

// attach listeners/event handlers
scan.on('json', handleJsonFiles)
    .on('dir', handleDirectories)
    .on('error', console.error);

// begin scan, convert emitted pathnames to absolute
scan.absolutely([pathA, pathB]);

A contrived but functional example including helper functions. This 1) outputs the file size of all JSON files, 2) outputs the modification dates of every directory, and 3) ignores 'node_modules', and '.git' directories. Note the new operator is optional, and is not used in this example.

var Scanfs = require('scanfs');

// add a 'json' custom event to override 'file' event for .json files
function jsonType(pathname, stat) {
    if (stat.isFile() && pathname.match(/\.json$/)) return 'json';
}

// 'json' event handler to log file size
function showSize(err, pathname, stat) {
    console.log(pathname, 'is', stat.size, 'bytes');
}

// 'dir' event handler to log the modification date
function showMtime(err, pathname, stat) {
    console.log(pathname, 'was modified on', stat.mtime);
}

// 'done' handler
function showCount(err, count) {
    console.log('done!', count, 'items processed.');
}

// instantiate with ignore patterns, and a custom event function
Scanfs([/\/node_modules$/, '.git'], jsonType)
    .on('json', showSize)
    .on('dir', showMtime)
    .on('error', console.error)
    .relatively('.'); // begin scan, returned paths are relative

Also see ./examples/.

methods

Scanfs extends node's EventEmitter, so all of it's methods are also available.

Class Scan(ignore, typerFn)

Returns a scanfs instance. Using new is optional. Parameters:

ignore optional string, regex, or array of strings and/or regexes. The strings or regexes, if matched against the item pathname, cause the ignored event to get fired (instead of file, dir, etc.).
typerFn optional function for customizing events. See custom events below.

scan.on(eventName, callback)

Attach listener callback to an event. Chainable. See events below.

scan.relatively(paths)

Start scanning. Pathnames emitted to listeners are relative to the current working directory if the path arguments are also relative to the current working directory. If the path parameter(s) are absolute, then the pathnames emittted will also be absolute.

paths string or array of strings, pathnames to scan recursively.

scan.absolutely(paths)

Start scanning. Pathnames are converted to absolute with path.resolve.

paths string or array of strings, pathnames to scan recursively.

events

scan.on('file', function(err, pathname, stat) {})

The scanned item was a regular file, or a symlink to an existing file.

err always null
pathname string path of file
stat fs.Stats object of file

scan.on('dir', function(err, pathname, stat) {})

The scanned item was a regular directory, or a symlink to an existing directory.

err always null
pathname string path of file
stat fs.Stats object of file

scan.on('other', function(err, pathname, stat) {})

Item was not a directory or file; i.e. socket, tty, fifo, etc.

err always null
pathname string path of file
stat fs.Stats object of file

scan.on('ignored', function(err, pathname, stat) {})

Emitted for items whose pathnames to ignore, as matched by a string or regex passed as the first parameter to the constructor.

err always null
pathname string path of file
stat fs.Stats object of file

scan.on('error', function(err, pathname) {})

err the Error object returned by fs.stat()
pathname string path of file

scan.on('*', function(err, pathname, stat, type) {})

A wildcard event, emitted for every event type except done.

err null, or the Error object returned by fs.stat()
pathname string path of file
stat fs.Stats object of file
type string event name

scan.on('done', function(err, count) { })

Signals file system scanning is complete.

err always null
count total number of filesystem items scanned

custom events

You can assign a custom event categorization function to Scan.typer, or pass it as the second parameter to the constructor. The categorization function is called for every non-error filesystem item, with the following two parameters:

pathname a string pathname of the item scanned
stat an fs.Stats object for the item scanned (see http://bit.ly/Sb0KRd or man 2 stat for more information about stat's properties)

If the categorization function returns a falsey value, then the default event is emitted. Otherwise, the return value is used as the event name.

Note that if the original event name was changed from dir to something else, then scanfs will not scan the associated directory.