What is module-deps?
The module-deps npm package is a tool for analyzing the dependency graph of Node.js modules. It parses the require() calls in a given entry file and recursively resolves the dependencies, providing a detailed graph of all the modules and their interconnections.
What are module-deps's main functionalities?
Dependency Graph Generation
This feature allows you to generate a JSON file that represents the dependency graph of a given entry file. The code sample demonstrates how to use module-deps to analyze 'entry.js' and output the dependency graph to 'deps.json'.
const mdeps = require('module-deps');
const JSONStream = require('JSONStream');
const fs = require('fs');
const md = mdeps();
md.pipe(JSONStream.stringify()).pipe(fs.createWriteStream('deps.json'));
md.end({ file: 'entry.js' });
Custom Resolvers
This feature allows you to provide custom resolution logic for resolving module paths. The code sample shows how to use a custom resolver function to handle module resolution.
const mdeps = require('module-deps');
const JSONStream = require('JSONStream');
const fs = require('fs');
const md = mdeps({
resolve: (id, parent, cb) => {
// Custom resolution logic
cb(null, id);
}
});
md.pipe(JSONStream.stringify()).pipe(fs.createWriteStream('deps.json'));
md.end({ file: 'entry.js' });
Transform Streams
This feature allows you to apply transform streams to the source files before they are parsed. The code sample demonstrates how to replace all instances of 'require' with 'customRequire' in the source files.
const mdeps = require('module-deps');
const through = require('through2');
const JSONStream = require('JSONStream');
const fs = require('fs');
const md = mdeps({
transform: (file) => {
return through(function (buf, enc, next) {
this.push(buf.toString('utf8').replace(/require/g, 'customRequire'));
next();
});
}
});
md.pipe(JSONStream.stringify()).pipe(fs.createWriteStream('deps.json'));
md.end({ file: 'entry.js' });
Other packages similar to module-deps
browserify
Browserify is a tool that allows you to bundle up all of your JavaScript dependencies for the browser. It also provides a way to analyze the dependency graph of your modules. Compared to module-deps, Browserify offers a more comprehensive solution for bundling and dependency management, including support for various plugins and transforms.
webpack
Webpack is a powerful module bundler for JavaScript applications. It analyzes the dependency graph of your modules and bundles them into a single file or multiple chunks. Webpack provides a rich ecosystem of plugins and loaders, making it more versatile than module-deps for complex build processes.
rollup
Rollup is a module bundler for JavaScript that focuses on ES6 modules. It provides tree-shaking capabilities to remove unused code from the final bundle. While module-deps focuses on dependency graph analysis, Rollup is more geared towards optimizing and bundling ES6 modules.
module-deps
walk the dependency graph to generate json output that can be fed into
browser-pack
example
var mdeps = require('module-deps');
var JSONStream = require('JSONStream');
var stringify = JSONStream.stringify();
stringify.pipe(process.stdout);
var file = __dirname + '/files/main.js';
mdeps(file).pipe(stringify);
output:
$ node example/deps.js
[
{"id":"/home/substack/projects/module-deps/example/files/main.js","source":"var foo = require('./foo');\nconsole.log('main: ' + foo(5));\n","entry":true,"deps":{"./foo":"/home/substack/projects/module-deps/example/files/foo.js"}}
,
{"id":"/home/substack/projects/module-deps/example/files/foo.js","source":"var bar = require('./bar');\n\nmodule.exports = function (n) {\n return n * 111 + bar(n);\n};\n","deps":{"./bar":"/home/substack/projects/module-deps/example/files/bar.js"}}
,
{"id":"/home/substack/projects/module-deps/example/files/bar.js","source":"module.exports = function (n) {\n return n * 100;\n};\n","deps":{}}
]
and you can feed this json data into
browser-pack:
$ node example/deps.js | browser-pack | node
main: 1055
usage
usage: module-deps [files]
generate json output from each entry file
methods
var mdeps = require('module-deps')
mdeps(files, opts={})
Return a readable stream of javascript objects from an array of filenames
files
.
Optionally pass in some opts
:
-
opts.transform - a string or array of string transforms (see below)
-
opts.transformKey - an array path of strings showing where to look in the
package.json for source transformations. If falsy, don't look at the
package.json at all.
-
opts.resolve - custom resolve function using the
opts.resolve(id, parent, cb)
signature that
browser-resolve has
-
opts.packageFilter - transform the parsed package.json contents before using
the values. opts.packageFilter(pkg)
should return the new pkg
object to use.
transforms
module-deps can be configured to run source transformations on files before
parsing them for require()
calls. These transforms are useful if you want to
compile a language like coffeescript on the fly or
if you want to load static assets into your bundle by parsing the AST for
fs.readFileSync()
calls.
If the transform is a function, it should take the file
name as an argument
and return a through stream that will be written file contents and should output
the new transformed file contents.
If the transform is a string, it is treated as a module name that will resolve
to a module that is expected to follow this format:
var through = require('through');
module.exports = function (file) { return through() };
You don't necessarily need to use the
through module to create a
readable/writable filter stream for transforming file contents, but this is an
easy way to do it.
When you call mdeps()
with an opts.transform
, the transformations you
specify will not be run for any files in node_modules/. This is because modules
you include should be self-contained and not need to worry about guarding
themselves against transformations that may happen upstream.
Modules can apply their own transformations by setting a transformation pipeline
in their package.json at the opts.transformKey
path. These transformations
only apply to the files directly in the module itself, not to the module's
dependants nor to its dependencies.
install
With npm, to get the module do:
npm install module-deps
and to get the module-deps
command do:
npm install -g module-deps
license
MIT