resolve

What is resolve?

The resolve npm package is a module for resolving file paths within a project. It is particularly useful for resolving the path of a module as Node.js would, taking into account node_modules folders and the package.json file. It can be used both programmatically and as a command-line tool.

What are resolve's main functionalities?

Asynchronously resolve the path of a module

This feature allows you to asynchronously find the path of a module from a given base directory. The callback receives the resolved path or an error if the module cannot be found.

const resolve = require('resolve');
resolve('module_name', { basedir: '/some/path' }, function (err, res) {
  if (err) console.error(err);
  else console.log(res);
});

Synchronously resolve the path of a module

This feature allows you to synchronously find the path of a module from a given base directory. It either returns the resolved path or throws an error if the module cannot be found.

const resolve = require('resolve');
try {
  const res = resolve.sync('module_name', { basedir: '/some/path' });
  console.log(res);
} catch (err) {
  console.error(err);
}

Resolve a module with custom package filter

This feature allows you to specify a custom filter function to modify the package data before the resolution process. This can be useful for redirecting the main entry point of a package.

const resolve = require('resolve');
const opts = {
  packageFilter: function (pkg) {
    if (pkg.main) {
      pkg.main = 'some-other-file.js';
    }
    return pkg;
  }
};
resolve('module_name', opts, function (err, res) {
  if (err) console.error(err);
  else console.log(res);
});

Command-line interface

The resolve package also provides a command-line interface (CLI) that can be used to resolve the path of a module from the command line.

$ resolve module_name --basedir=/some/path

Other packages similar to resolve

enhanced-resolve

enhanced-resolve is a library that offers more advanced resolution options and plugins, similar to webpack's resolver. It is more complex and configurable compared to resolve.

browser-resolve

browser-resolve is a resolve algorithm that takes browser field in package.json into account. It is similar to resolve but is specifically designed for browser environments.

require-resolve

require-resolve is a package that mimics node's require.resolve function. It is similar to resolve but focuses on mimicking the behavior of Node.js's native require.resolve method.

README

resolve

Implements the node require.resolve() algorithm except you can pass in the file to compute paths relatively to along with your own require.paths without updating the global copy (which doesn't even work in node >=0.5).

methods

var resolve = require('resolve');

resolve.sync(pkg, opts)

Synchronously search for the package/filename string pkg according to the require.resolve() algorithm for X=pkg and Y=opts.basedir.

Default values for opts:

{
    paths : [],
    basedir : __dirname,
    extensions : [ '.js' ],
    readFileSync : fs.readFileSync,
    isFile : function (file) {
        return path.existSync(file) && fs.statSync(file).isFile()
    }
}

Optionally you can specify a opts.packageFilter function to map the contents of JSON.parse()'d package.json files.

If nothing is found, all of the directories in opts.paths are searched.

resolve.isCore(pkg)

Return whether a package is in core.