resolve

implements the node require.resolve() algorithm such that you can require.resolve() on behalf of a file asynchronously and synchronously

example

asynchronously resolve:

1var resolve = require('resolve/async'); // or, require('resolve')
2resolve('tap', { basedir: __dirname }, function (err, res) {
3    if (err) console.error(err);
4    else console.log(res);
5});

$ node example/async.js
/home/substack/projects/node-resolve/node_modules/tap/lib/main.js

synchronously resolve:

1var resolve = require('resolve/sync'); // or, `require('resolve').sync
2var res = resolve('tap', { basedir: __dirname });
3console.log(res);

$ node example/sync.js
/home/substack/projects/node-resolve/node_modules/tap/lib/main.js

methods

1var resolve = require('resolve');
2var async = require('resolve/async');
3var sync = require('resolve/sync');

For both the synchronous and asynchronous methods, errors may have any of the following err.code values:

• MODULE_NOT_FOUND: the given path string (id) could not be resolved to a module
• INVALID_BASEDIR: the specified opts.basedir doesn't exist, or is not a directory
• INVALID_PACKAGE_MAIN: a package.json was encountered with an invalid main property (eg. not a string)

resolve(id, opts={}, cb)

Asynchronously resolve the module path string id into cb(err, res [, pkg]), where pkg (if defined) is the data from package.json.

options are:

• opts.basedir - directory to begin resolving from

• opts.package - package.json data applicable to the module being loaded

• opts.extensions - array of file extensions to search in order

• opts.includeCoreModules - set to false to exclude node core modules (e.g. fs) from the search

• opts.readFile - how to read files asynchronously

• opts.isFile - function to asynchronously test whether a file exists

• opts.isDirectory - function to asynchronously test whether a file exists and is a directory

• opts.realpath - function to asynchronously resolve a potential symlink to its real path

• opts.readPackage(readFile, pkgfile, cb) - function to asynchronously read and parse a package.json file

  • readFile - the passed opts.readFile or fs.readFile if not specified
  • pkgfile - path to package.json
  • cb - callback. a SyntaxError error argument will be ignored, all other error arguments will be treated as an error.

• opts.packageFilter(pkg, pkgfile, dir) - transform the parsed package.json contents before looking at the "main" field

  • pkg - package data
  • pkgfile - path to package.json
  • dir - directory that contains package.json

• opts.pathFilter(pkg, path, relativePath) - transform a path within a package

  • pkg - package data
  • path - the path being resolved
  • relativePath - the path relative from the package.json location
  • returns - a relative path that will be joined from the package.json location

• opts.paths - require.paths array to use if nothing is found on the normal node_modules recursive walk (probably don't use this)

  For advanced users, paths can also be a opts.paths(request, start, opts) function

  • request - the import specifier being resolved
  • start - lookup path
  • getNodeModulesDirs - a thunk (no-argument function) that returns the paths using standard node_modules resolution
  • opts - the resolution options

• opts.packageIterator(request, start, opts) - return the list of candidate paths where the packages sources may be found (probably don't use this)

  • request - the import specifier being resolved
  • start - lookup path
  • getPackageCandidates - a thunk (no-argument function) that returns the paths using standard node_modules resolution
  • opts - the resolution options

• opts.moduleDirectory - directory (or directories) in which to recursively look for modules. default: "node_modules"

• opts.preserveSymlinks - if true, doesn't resolve basedir to real path before resolving. This is the way Node resolves dependencies when executed with the --preserve-symlinks flag.

default opts values:

1{
2    paths: [],
3    basedir: __dirname,
4    extensions: ['.js'],
5    includeCoreModules: true,
6    readFile: fs.readFile,
7    isFile: function isFile(file, cb) {
8        fs.stat(file, function (err, stat) {
9            if (!err) {
10                return cb(null, stat.isFile() || stat.isFIFO());
11            }
12            if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
13            return cb(err);
14        });
15    },
16    isDirectory: function isDirectory(dir, cb) {
17        fs.stat(dir, function (err, stat) {
18            if (!err) {
19                return cb(null, stat.isDirectory());
20            }
21            if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
22            return cb(err);
23        });
24    },
25    realpath: function realpath(file, cb) {
26        var realpath = typeof fs.realpath.native === 'function' ? fs.realpath.native : fs.realpath;
27        realpath(file, function (realPathErr, realPath) {
28            if (realPathErr && realPathErr.code !== 'ENOENT') cb(realPathErr);
29            else cb(null, realPathErr ? file : realPath);
30        });
31    },
32    readPackage: function defaultReadPackage(readFile, pkgfile, cb) {
33        readFile(pkgfile, function (readFileErr, body) {
34            if (readFileErr) cb(readFileErr);
35            else {
36                try {
37                    var pkg = JSON.parse(body);
38                    cb(null, pkg);
39                } catch (jsonErr) {
40                    cb(jsonErr);
41                }
42            }
43        });
44    },
45    moduleDirectory: 'node_modules',
46    preserveSymlinks: false
47}

resolve.sync(id, opts)

Synchronously resolve the module path string id, returning the result and throwing an error when id can't be resolved.

options are:

• opts.basedir - directory to begin resolving from

• opts.extensions - array of file extensions to search in order

• opts.includeCoreModules - set to false to exclude node core modules (e.g. fs) from the search

• opts.readFileSync - how to read files synchronously

• opts.isFile - function to synchronously test whether a file exists

• opts.isDirectory - function to synchronously test whether a file exists and is a directory

• opts.realpathSync - function to synchronously resolve a potential symlink to its real path

• opts.readPackageSync(readFileSync, pkgfile) - function to synchronously read and parse a package.json file. a thrown SyntaxError will be ignored, all other exceptions will propagate.

  • readFileSync - the passed opts.readFileSync or fs.readFileSync if not specified
  • pkgfile - path to package.json

• opts.packageFilter(pkg, pkgfile, dir) - transform the parsed package.json contents before looking at the "main" field

  • pkg - package data
  • pkgfile - path to package.json
  • dir - directory that contains package.json

• opts.pathFilter(pkg, path, relativePath) - transform a path within a package

  • pkg - package data
  • path - the path being resolved
  • relativePath - the path relative from the package.json location
  • returns - a relative path that will be joined from the package.json location

• opts.paths - require.paths array to use if nothing is found on the normal node_modules recursive walk (probably don't use this)

  For advanced users, paths can also be a opts.paths(request, start, opts) function

  • request - the import specifier being resolved
  • start - lookup path
  • getNodeModulesDirs - a thunk (no-argument function) that returns the paths using standard node_modules resolution
  • opts - the resolution options

• opts.packageIterator(request, start, opts) - return the list of candidate paths where the packages sources may be found (probably don't use this)

  • request - the import specifier being resolved
  • start - lookup path
  • getPackageCandidates - a thunk (no-argument function) that returns the paths using standard node_modules resolution
  • opts - the resolution options

• opts.moduleDirectory - directory (or directories) in which to recursively look for modules. default: "node_modules"

• opts.preserveSymlinks - if true, doesn't resolve basedir to real path before resolving. This is the way Node resolves dependencies when executed with the --preserve-symlinks flag.

default opts values:

1{
2    paths: [],
3    basedir: __dirname,
4    extensions: ['.js'],
5    includeCoreModules: true,
6    readFileSync: fs.readFileSync,
7    isFile: function isFile(file) {
8        try {
9            var stat = fs.statSync(file);
10        } catch (e) {
11            if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
12            throw e;
13        }
14        return stat.isFile() || stat.isFIFO();
15    },
16    isDirectory: function isDirectory(dir) {
17        try {
18            var stat = fs.statSync(dir);
19        } catch (e) {
20            if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
21            throw e;
22        }
23        return stat.isDirectory();
24    },
25    realpathSync: function realpathSync(file) {
26        try {
27            var realpath = typeof fs.realpathSync.native === 'function' ? fs.realpathSync.native : fs.realpathSync;
28            return realpath(file);
29        } catch (realPathErr) {
30            if (realPathErr.code !== 'ENOENT') {
31                throw realPathErr;
32            }
33        }
34        return file;
35    },
36    readPackageSync: function defaultReadPackageSync(readFileSync, pkgfile) {
37        return JSON.parse(readFileSync(pkgfile));
38    },
39    moduleDirectory: 'node_modules',
40    preserveSymlinks: false
41}

install

With npm do:

1npm install resolve

license

MIT