125 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			125 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# memfs
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[![][chat-badge]][chat] [![][npm-badge]][npm-url] [![][travis-badge]][travis-url]
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In-memory file-system with [Node's `fs` API](https://nodejs.org/api/fs.html).
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- Node's `fs` API implemented, see [_old API Status_](./docs/api-status.md), [missing list](https://github.com/streamich/memfs/issues/735), [missing `opendir`](https://github.com/streamich/memfs/issues/663)
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- Stores files in memory, in `Buffer`s
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- Throws sameish\* errors as Node.js
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- Has concept of _i-nodes_
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- Implements _hard links_
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- Implements _soft links_ (aka symlinks, symbolic links)
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- Permissions may\* be implemented in the future
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- Can be used in browser, see [`memfs-webpack`](https://github.com/streamich/memfs-webpack)
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### Install
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```shell
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npm install --save memfs
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```
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## Usage
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```js
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import { fs } from 'memfs';
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fs.writeFileSync('/hello.txt', 'World!');
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fs.readFileSync('/hello.txt', 'utf8'); // World!
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```
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Create a file system from a plain JSON:
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```js
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import { fs, vol } from 'memfs';
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const json = {
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  './README.md': '1',
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  './src/index.js': '2',
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  './node_modules/debug/index.js': '3',
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};
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vol.fromJSON(json, '/app');
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fs.readFileSync('/app/README.md', 'utf8'); // 1
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vol.readFileSync('/app/src/index.js', 'utf8'); // 2
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```
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Export to JSON:
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```js
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vol.writeFileSync('/script.sh', 'sudo rm -rf *');
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vol.toJSON(); // {"/script.sh": "sudo rm -rf *"}
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```
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Use it for testing:
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```js
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vol.writeFileSync('/foo', 'bar');
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expect(vol.toJSON()).toEqual({ '/foo': 'bar' });
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```
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Create as many filesystem volumes as you need:
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```js
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import { Volume } from 'memfs';
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const vol = Volume.fromJSON({ '/foo': 'bar' });
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vol.readFileSync('/foo'); // bar
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const vol2 = Volume.fromJSON({ '/foo': 'bar 2' });
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vol2.readFileSync('/foo'); // bar 2
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```
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Use `memfs` together with [`unionfs`][unionfs] to create one filesystem
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from your in-memory volumes and the real disk filesystem:
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```js
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import * as fs from 'fs';
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import { ufs } from 'unionfs';
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ufs.use(fs).use(vol);
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ufs.readFileSync('/foo'); // bar
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```
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Use [`fs-monkey`][fs-monkey] to monkey-patch Node's `require` function:
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```js
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import { patchRequire } from 'fs-monkey';
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vol.writeFileSync('/index.js', 'console.log("hi world")');
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patchRequire(vol);
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require('/index'); // hi world
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```
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## Docs
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- [Reference](./docs/reference.md)
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- [Relative paths](./docs/relative-paths.md)
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- [API status](./docs/api-status.md)
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- [Dependencies](./docs/dependencies.md)
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## See also
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- [`spyfs`][spyfs] - spies on filesystem actions
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- [`unionfs`][unionfs] - creates a union of multiple filesystem volumes
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- [`linkfs`][linkfs] - redirects filesystem paths
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- [`fs-monkey`][fs-monkey] - monkey-patches Node's `fs` module and `require` function
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- [`libfs`](https://github.com/streamich/full-js/blob/master/src/lib/fs.ts) - real filesystem (that executes UNIX system calls) implemented in JavaScript
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[chat]: https://onp4.com/@vadim/~memfs
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[chat-badge]: https://img.shields.io/badge/Chat-%F0%9F%92%AC-green?style=flat&logo=chat&link=https://onp4.com/@vadim/~memfs
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[npm-url]: https://www.npmjs.com/package/memfs
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[npm-badge]: https://img.shields.io/npm/v/memfs.svg
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[travis-url]: https://travis-ci.org/streamich/memfs
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[travis-badge]: https://travis-ci.org/streamich/memfs.svg?branch=master
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[memfs]: https://github.com/streamich/memfs
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[unionfs]: https://github.com/streamich/unionfs
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[linkfs]: https://github.com/streamich/linkfs
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[spyfs]: https://github.com/streamich/spyfs
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[fs-monkey]: https://github.com/streamich/fs-monkey
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## License
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[Unlicense](./LICENSE) - public domain.
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