280 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
		
		
			
		
	
	
			280 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
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								# resolve
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								implements the [node `require.resolve()`
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								algorithm](https://nodejs.org/api/modules.html#modules_all_together)
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								such that you can `require.resolve()` on behalf of a file asynchronously and
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								synchronously
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								[](http://travis-ci.org/browserify/resolve)
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								# example
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								asynchronously resolve:
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								```js
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								var resolve = require('resolve');
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								resolve('tap', { basedir: __dirname }, function (err, res) {
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								    if (err) console.error(err);
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								    else console.log(res);
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								});
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								```
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								```
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								$ node example/async.js
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								/home/substack/projects/node-resolve/node_modules/tap/lib/main.js
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								```
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								synchronously resolve:
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								```js
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								var resolve = require('resolve');
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								var res = resolve.sync('tap', { basedir: __dirname });
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								console.log(res);
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								```
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								```
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								$ node example/sync.js
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								/home/substack/projects/node-resolve/node_modules/tap/lib/main.js
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								```
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								# methods
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								```js
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								var resolve = require('resolve');
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								```
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								For both the synchronous and asynchronous methods, errors may have any of the following `err.code` values:
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								- `MODULE_NOT_FOUND`: the given path string (`id`) could not be resolved to a module
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								- `INVALID_BASEDIR`: the specified `opts.basedir` doesn't exist, or is not a directory
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								- `INVALID_PACKAGE_MAIN`: a `package.json` was encountered with an invalid `main` property (eg. not a string)
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								## resolve(id, opts={}, cb)
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								Asynchronously resolve the module path string `id` into `cb(err, res [, pkg])`, where `pkg` (if defined) is the data from `package.json`.
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								options are:
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								* opts.basedir - directory to begin resolving from
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								* opts.package - `package.json` data applicable to the module being loaded
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								* opts.extensions - array of file extensions to search in order
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								* opts.includeCoreModules - set to `false` to exclude node core modules (e.g. `fs`) from the search
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								* opts.readFile - how to read files asynchronously
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								* opts.isFile - function to asynchronously test whether a file exists
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								* opts.isDirectory - function to asynchronously test whether a directory exists
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								* opts.realpath - function to asynchronously resolve a potential symlink to its real path
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								* `opts.readPackage(readFile, pkgfile, cb)` - function to asynchronously read and parse a package.json file
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								  * readFile - the passed `opts.readFile` or `fs.readFile` if not specified
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								  * pkgfile - path to package.json
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								  * cb - callback
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								* `opts.packageFilter(pkg, pkgfile, dir)` - transform the parsed package.json contents before looking at the "main" field
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								  * pkg - package data
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								  * pkgfile - path to package.json
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								  * dir - directory for package.json
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								* `opts.pathFilter(pkg, path, relativePath)` - transform a path within a package
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								  * pkg - package data
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								  * path - the path being resolved
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								  * relativePath - the path relative from the package.json location
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								  * returns - a relative path that will be joined from the package.json location
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								* opts.paths - require.paths array to use if nothing is found on the normal `node_modules` recursive walk (probably don't use this)
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								  For advanced users, `paths` can also be a `opts.paths(request, start, opts)` function
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								    * request - the import specifier being resolved
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								    * start - lookup path
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								    * getNodeModulesDirs - a thunk (no-argument function) that returns the paths using standard `node_modules` resolution
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								    * opts - the resolution options
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								* `opts.packageIterator(request, start, opts)` - return the list of candidate paths where the packages sources may be found (probably don't use this)
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								    * request - the import specifier being resolved
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								    * start - lookup path
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								    * getPackageCandidates - a thunk (no-argument function) that returns the paths using standard `node_modules` resolution
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								    * opts - the resolution options
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								* opts.moduleDirectory - directory (or directories) in which to recursively look for modules. default: `"node_modules"`
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								* opts.preserveSymlinks - if true, doesn't resolve `basedir` to real path before resolving.
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								This is the way Node resolves dependencies when executed with the [--preserve-symlinks](https://nodejs.org/api/all.html#cli_preserve_symlinks) flag.
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								**Note:** this property is currently `true` by default but it will be changed to
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								`false` in the next major version because *Node's resolution algorithm does not preserve symlinks by default*.
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								default `opts` values:
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								```js
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								{
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								    paths: [],
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								    basedir: __dirname,
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								    extensions: ['.js'],
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								    includeCoreModules: true,
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								    readFile: fs.readFile,
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								    isFile: function isFile(file, cb) {
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								        fs.stat(file, function (err, stat) {
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								            if (!err) {
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								                return cb(null, stat.isFile() || stat.isFIFO());
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								            }
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								            if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
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								            return cb(err);
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								        });
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								    },
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								    isDirectory: function isDirectory(dir, cb) {
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								        fs.stat(dir, function (err, stat) {
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								            if (!err) {
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								                return cb(null, stat.isDirectory());
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								            }
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								            if (err.code === 'ENOENT' || err.code === 'ENOTDIR') return cb(null, false);
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								            return cb(err);
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								        });
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								    },
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								    realpath: function realpath(file, cb) {
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								        var realpath = typeof fs.realpath.native === 'function' ? fs.realpath.native : fs.realpath;
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								        realpath(file, function (realPathErr, realPath) {
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								            if (realPathErr && realPathErr.code !== 'ENOENT') cb(realPathErr);
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								            else cb(null, realPathErr ? file : realPath);
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								        });
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								    },
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								    readPackage: function defaultReadPackage(readFile, pkgfile, cb) {
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								        readFile(pkgfile, function (readFileErr, body) {
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								            if (readFileErr) cb(readFileErr);
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								            else {
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								                try {
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								                    var pkg = JSON.parse(body);
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								                    cb(null, pkg);
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								                } catch (jsonErr) {
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								                    cb(null);
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								                }
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								            }
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								        });
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								    },
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								    moduleDirectory: 'node_modules',
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								    preserveSymlinks: true
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								}
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								```
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								## resolve.sync(id, opts)
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								Synchronously resolve the module path string `id`, returning the result and
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								throwing an error when `id` can't be resolved.
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								options are:
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								* opts.basedir - directory to begin resolving from
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								* opts.extensions - array of file extensions to search in order
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								* opts.includeCoreModules - set to `false` to exclude node core modules (e.g. `fs`) from the search
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								* opts.readFileSync - how to read files synchronously
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								* opts.isFile - function to synchronously test whether a file exists
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								* opts.isDirectory - function to synchronously test whether a directory exists
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								* opts.realpathSync - function to synchronously resolve a potential symlink to its real path
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								* `opts.readPackageSync(readFileSync, pkgfile)` - function to synchronously read and parse a package.json file
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								  * readFileSync - the passed `opts.readFileSync` or `fs.readFileSync` if not specified
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								  * pkgfile - path to package.json
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								* `opts.packageFilter(pkg, dir)` - transform the parsed package.json contents before looking at the "main" field
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								  * pkg - package data
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								  * dir - directory for package.json (Note: the second argument will change to "pkgfile" in v2)
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								* `opts.pathFilter(pkg, path, relativePath)` - transform a path within a package
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								  * pkg - package data
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								  * path - the path being resolved
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								  * relativePath - the path relative from the package.json location
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								  * returns - a relative path that will be joined from the package.json location
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								* opts.paths - require.paths array to use if nothing is found on the normal `node_modules` recursive walk (probably don't use this)
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								  For advanced users, `paths` can also be a `opts.paths(request, start, opts)` function
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								    * request - the import specifier being resolved
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								    * start - lookup path
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								    * getNodeModulesDirs - a thunk (no-argument function) that returns the paths using standard `node_modules` resolution
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								    * opts - the resolution options
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								* `opts.packageIterator(request, start, opts)` - return the list of candidate paths where the packages sources may be found (probably don't use this)
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								    * request - the import specifier being resolved
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								    * start - lookup path
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								    * getPackageCandidates - a thunk (no-argument function) that returns the paths using standard `node_modules` resolution
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								    * opts - the resolution options
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								* opts.moduleDirectory - directory (or directories) in which to recursively look for modules. default: `"node_modules"`
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								* opts.preserveSymlinks - if true, doesn't resolve `basedir` to real path before resolving.
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								This is the way Node resolves dependencies when executed with the [--preserve-symlinks](https://nodejs.org/api/all.html#cli_preserve_symlinks) flag.
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								**Note:** this property is currently `true` by default but it will be changed to
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								`false` in the next major version because *Node's resolution algorithm does not preserve symlinks by default*.
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								default `opts` values:
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								```js
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								{
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								    paths: [],
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								    basedir: __dirname,
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								    extensions: ['.js'],
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								    includeCoreModules: true,
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								    readFileSync: fs.readFileSync,
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								    isFile: function isFile(file) {
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								        try {
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								            var stat = fs.statSync(file);
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								        } catch (e) {
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								            if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
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								            throw e;
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								        }
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								        return stat.isFile() || stat.isFIFO();
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								    },
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								    isDirectory: function isDirectory(dir) {
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								        try {
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								            var stat = fs.statSync(dir);
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								        } catch (e) {
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								            if (e && (e.code === 'ENOENT' || e.code === 'ENOTDIR')) return false;
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								            throw e;
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								        }
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								        return stat.isDirectory();
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								    },
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								    realpathSync: function realpathSync(file) {
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								        try {
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								            var realpath = typeof fs.realpathSync.native === 'function' ? fs.realpathSync.native : fs.realpathSync;
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								            return realpath(file);
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								        } catch (realPathErr) {
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								            if (realPathErr.code !== 'ENOENT') {
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								                throw realPathErr;
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								            }
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								        }
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								        return file;
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								 | 
							
								    },
							 | 
						||
| 
								 | 
							
								    readPackageSync: function defaultReadPackageSync(readFileSync, pkgfile) {
							 | 
						||
| 
								 | 
							
								        var body = readFileSync(pkgfile);
							 | 
						||
| 
								 | 
							
								        try {
							 | 
						||
| 
								 | 
							
								            var pkg = JSON.parse(body);
							 | 
						||
| 
								 | 
							
								            return pkg;
							 | 
						||
| 
								 | 
							
								        } catch (jsonErr) {}
							 | 
						||
| 
								 | 
							
								    },
							 | 
						||
| 
								 | 
							
								    moduleDirectory: 'node_modules',
							 | 
						||
| 
								 | 
							
								    preserveSymlinks: true
							 | 
						||
| 
								 | 
							
								}
							 | 
						||
| 
								 | 
							
								```
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								# install
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								With [npm](https://npmjs.org) do:
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								```sh
							 | 
						||
| 
								 | 
							
								npm install resolve
							 | 
						||
| 
								 | 
							
								```
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								# license
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								MIT
							 |