251 lines
8.9 KiB
Markdown
251 lines
8.9 KiB
Markdown
# 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.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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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.readFile - 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.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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},
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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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# install
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With [npm](https://npmjs.org) do:
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```sh
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npm install resolve
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```
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# license
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MIT
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