Doloop NPM | npm.io

doloop

doloop is a small tool for working with files in a directory. It allows you to loop through all the files and perform any number of transforms on the files. It can be used as a full on build tool, or a simple tool to make your life easier when working with a lot of files.

Getting Started

DoLoop requires Node and NPM to be installed.

Install doloop using npm install doloop. Then create a blank JS file and require('doloop') at the top.

var DoLoop = require('doloop');

Your First Loop

Looping is really easy, take a look at this basic example:

DoLoop()
.loop( function( filename, data ){
   console.log( filename );
});

In the above example we are simply looping over all the files in the default directory (the folder you ran npm install doloop in) and using console.log to print the name of each file.

You can do anything you want within the loop.
For instance, you can choose to do certain things to files if they match a filename:

var fs = require('fs');
var DoLoop = require('doloop');
DoLoop()
.cd('scripts/')
.loop( function( filename, data ) {
  if ( filename === "main.js" ) {
    // do something with the file: this.directory + "/" + filename
  }
});

Uses / Examples

doloop can be a useful tool in your build flow that helps speed up tackling repetitive tasks. However, by itself doloop cannot do much. It's usefulness comes from how you hook into the loops and transform the files it provides.

Concatenate scripts or strings
Image processing on a folder of images
To precompile templates into compiled HTML using Handlebars
As a static blog generator
To transform markdown files into HTML

API

The DoLoop constructor

You need to create a new DoLoop object to kick everything off. You can store it as a variable or create it anonymously. Optionally, you can pass one argument that will set the directory.

var myLoop = DoLoop() // store as myLoop
DoLoop() // self-invoked

From there you'll get to doing stuff by chaining methods on this object. The two most important methods are loop() and build(), read about those below.

Properties

DoLoop.directory

This is a String value of the current directory that DoLoop is working in.

DoLoop.files

This is an array of filenames that gets built up during the loop() method. This property is useful when used within a done() callback function. With it, you can see the files that were looped through.

Methods

You can chain methods, for example cd(path).readEncoding('utf8').loop(callback) but you can not chain more than one loop. To create several loops simply create multiple DoLoop constructors.

cd ( path )

An alias of the changeDirectory method.

changeDirectory ( path )

path required the path to execute the loop in

Changes the directory relative to the path provided.

readEncoding ( encoding )

encoding required the encoding to use (for example: 'utf8')

Changes the encoding used by Node's fs.readFile function. If a null encoding is specified, then the raw buffer is returned. Use 'utf8' to return a utf8 string of the file contents.

loop ( regEx, callback )

regEx optional a regular expression for match filenames in the loop.
callback required the function to execute on each file looped through.

The callback function is passed two arguments (filename, data), where data is a raw buffer of the file contents (unless modified, for example using readEncoding('utf8')).

var concat = "";
DoLoop('scripts/')
.readEncoding('utf8')
.loop('.js+$', function(filename, data) {
  concat += data;
});

Here we are looping through all the files in scripts/ and adding the data from each file to concat. At first glance you may think you could use concat outside of the loop, however because this is working asynchronously concat will be an empty string. To use data created or modified in the loop use the build() method which is only fired after the preceding loop has finished.

build ( callback )

callback required the function to execute after the preceding loop has completed

The callback function is called after the loop is finished. It is not passed any arguments. The build method is a place to perform tasks after the loop has finished.

var concat = "";
DoLoop('scripts/')
.readEncoding('utf8')
.loop('.js+$' function(filename, data) {
  concat += data;
})
.done(function(){
  console.log(concat); // prints the data created during the loop  
});