161 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Markdown
		
	
	
	
			
		
		
	
	
			161 lines
		
	
	
		
			4.5 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/node-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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## 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.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.packageFilter - transform the parsed package.json contents before looking
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at the "main" field
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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
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node_modules recursive walk (probably don't use this)
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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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``` javascript
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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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    readFile: fs.readFile,
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    isFile: function (file, cb) {
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        fs.stat(file, function (err, stat) {
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            if (err && err.code === 'ENOENT') cb(null, false)
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            else if (err) cb(err)
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            else cb(null, stat.isFile())
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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.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.packageFilter(pkg, pkgfile)` - transform the parsed package.json
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* contents before looking at the "main" field
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* opts.paths - require.paths array to use if nothing is found on the normal
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node_modules recursive walk (probably don't use this)
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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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``` javascript
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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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    readFileSync: fs.readFileSync,
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    isFile: function (file) {
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        try { return fs.statSync(file).isFile() }
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        catch (e) { return false }
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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.isCore(pkg)
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Return whether a package is in core.
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# install
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With [npm](https://npmjs.org) do:
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```
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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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