0.1.6 • Public • Published

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Unifies javascript source files in the order you require

Getting started

The stable version of the node-neuter library can be installed from the npm package:

npm install neuter

Alternatively the latest version can be installed from git:

npm install

Then simply require node-neuter in your project

var neuter = require('neuter');



Node-neuter is based on and aims to extract the core functionality into a pure node library.

The main goal for node-neuter is to implement a pure node version of the grunt-neuter core, paving the road for implementations for both grunt and gulp, as described in grunt-neuter issue #47.

Although based on grunt-neuter, node-neuter is a rewrite using esprima in stead of regular expressions. As a result of this, node-neuter detects when require is overwritten with a local reference and will then ignore require statements as long as the local reference is in scope.

In contrast to grunt-neuter, node-neuter returns a SourceNode object, allowing for custom handling of the parsed code and/or map generation. Because node-neuter doesn't actually generate the source and map itself, the includesourcemap option and corresponding features have been dropped.


  1. Merges files into the main file on each call of require(file)

  2. Ignores calls to locally defined require methods

  3. Support for glob pathnames

  4. Guards against double inclusion

  5. Support for file blacklisting (files will be included raw)

  6. Support for pre-include templating

  7. Support for include basepath

  8. Unifies into a universal SourceNode object

  9. Support for the vynil virtual fyle format

  10. Passes all grunt-neuter unit tests, excluding those requiring the includesourcemap feature


  • make full use of Buffers
  • write testcases for parse(File, callback) interface
  • write documentation for parse(File, callback) interface
  • ...


Before reporting an issue, please check if the issue isn't reported already. If it isn't, please open an issue taking into account the bug reporting guidelines.

Optionally, if you're up for the challenge of fixing the issue, fork the repo. Commit the patch to your local branch (not the master branch) and send in a pull request. We love pull requests!

Special thanks go to

  • bschuedzig for reporting the very first bug and pull request



var Neuter = require('neuter');
var myNeuter = new Neuter();
myNeuter.parse('myfile.js', function(err, sourceNode) {
    if (err) {
        // ... handle error
    // ... use the unified sourceNode object to generate source or a map



Specifying a base path allows you to omit said portion of the filepath from your require statements. For example: when using basePath: "lib/js/" in your task options, require("lib/js/file.js"); can instead be written as require("file.js");. Note that the trailing slash must be included.

Type: String Default: ''


Specifying a filepath transform allows you to control the path to the file that actually gets concatenated. For example, when using filepathTransform: function(filepath){ return 'lib/js/' + filepath; } in your task options, require("lib/js/file.js"); can instead be written as require("file.js"); (This achieves the same result as specifying basePath: "lib/js/"). When used in conjunction with the basePath option, the base path will be prepended to the filepath argument and a second argument will be provided that is the directory of the file without the basePath.

Type: function Default: function(filepath){ return filepath; }


Type: String Default: (function() {\n\n{%= src %}\n\n})();


Neutered files will be joined on this string. If you're post-processing concatenated JavaScript files with a minifier, you may need to use a semicolon ';' as the separator although the semicolon at the end of the template should suffice.

Type: String Default: \n\n


A list of files being required that should not be checked for further require statements. Useful for libraries that support other module building methods and leave their requires around in a way that isn't meaningful to neutering.

Type: Array Default: []


Process source files before concatenating, either as templates or with a custom function. The delimiters default to neuter's own special type ({% %}), which helps avoid errors when requiring libraries like Underscore or Lo-Dash.

  • false - No processing will occur.
  • true - Process source files using [grunt.template.process][] without any data.
  • options object - Process source files using [grunt.template.process][], using the specified options.
  • function(src, filepath) - Process source files using the given function, called once for each file. The returned value will be used as source code.

Type: Boolean Object Function Default: false


Generating neutered source

var Neuter = require('neuter');
var myNeuter = new Neuter();
myNeuter.parse('myfile.js', function(err, sourceNode) {
    if (err) {
        // ... handle error
    var codeMap = sourceNode.toStringWithSourceMap({
        file: 'neutered.js',
    var neuteredSource = codeMap.code;

Generating source map

var Neuter = require('neuter');
var path = require('path');
var SourceMapConsumer = require('source-map').SourceMapConsumer;
var SourceMapGenerator = require('source-map').SourceMapGenerator;
var myNeuter = new Neuter();
myNeuter.parse('myfile.js', function(err, sourceNode) {
    if (err) {
        // ... handle error
    var codeMap = sourceNode.toStringWithSourceMap({
        file: 'neutered.js',
    var consumer = new SourceMapConsumer(;
    var generator = SourceMapGenerator.fromSourceMap(consumer);
    var newSourceMap = generator.toJSON();
    newSourceMap.file = path.basename(newSourceMap.file);
    var sourceMap = JSON.stringify(newSourceMap, null, '  ');


npm i neuter

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