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https://github.com/sobesednik/wrote

Promise-based write for Node.js
https://github.com/sobesednik/wrote

fs io nodejs promise read stream write

Last synced: 6 months ago
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Promise-based write for Node.js

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README 

          
# wrote



[![npm version](https://badge.fury.io/js/wrote.svg)](https://badge.fury.io/js/wrote)



Promise-based write and read operations for Node.js



## ES5



The package uses some newer language features. For your convenience, it's been

transpiled to be compatible with Node 4. You can use the following snippet.



```js

const wrote = require('wrote/es5/src/')

```



## `wrote.createWritable(path=: string): Promise.`



Create an open Writable stream to the file.



```js

const { Writable } = require('stream')

const path = require('path')

const HOME_DIR = require('os').homedir()

const { createWritable } = require('wrote')



const file = path.join(HOME_DIR, `wrote-${Math.floor(Math.random() * 1e5)}.data`);



(async () => {

    const ws = await createWritable(file)

    console.log(ws instanceof Writable) // true

    console.log(ws.path) // ~/wrote-35558.data

})()

```



If you don't have a file, a new one in the temp directory will be created for you.



```js

(async () => {

    const ws = await createWritable()

    console.log(ws instanceof Writable) // true

    console.log(ws.path) // /var/folders/s0/1h2g/T/wrote-48315.data

})()

```



## `wrote.exists(path: string): Promise.`



Check if the path on the filesystem exists. Throws if path is not accessible

due to permissions.



```js

const { exists } = require('wrote');



(async () => {

    await exists('unknown-path') // false

    await exists(__filename) // true

    await exists(__dirname) // true

})()

```



## `wrote.assertExists(path: string): Promise`



Check if the path on the filesystem exists, and throw if it does not, or cannot

be accessed.



```js

const { assertExists } = require('wrote');



(async () => {

    try {

        await assertExists('unknown-path')

    } catch (err) {

        console.log(err) // Path unknown-path does not exist.

    }

    await assertExists(__filename) // ok

})()

```



## `wrote.assertDoesNotExist(path: string): Promise`



Check if the path on the filesystem does not exists, and throw if it does, or

cannot be accessed.



```js

const { assertDoesNotExist } = require('wrote');



(async () => {

    try {

        await assertDoesNotExist(__filename)

    } catch (err) {

        console.log(err) // Path /wrote/examples/assert-does-not-exist.js exists.

    }

    await assertDoesNotExist('unknown-file') // ok

})()

```



## `wrote.clone({ from: string, to: string, regexes: [] }): Promise`



Clone a directory by copying contents of files and creating symlinks. Regular

expressions can be used to transform data being copied.



```js

const { clone } = require('wrote');



(async () => {

    const from = './directory'

    const to = './clone'



    await clone({

        from,

        to,

        regexes: [

            {

                re: /{{ name }}/g, // use /g flag for global replacements

                replacement: 'Garry',

            },

            {

                re: /{{ age }}/,

                replacement: '30',

            },

        ],

    })

    // or,

    // await clone({ to, from })

})()

```



## `wrote.erase(ws: Writable): Promise.`



Erase file and close stream.



```js

const { createWritable, erase } = require('wrote')

const { Writable } = require('stream')

const path = require('path')

const HOME_DIR = require('os').homedir()



const file = path.join(HOME_DIR, `wrote-${Math.floor(Math.random() * 1e5)}.data`);



(async () => {

    const ws = await createWritable(file)

    console.log(ws instanceof Writable) // true

    console.log(ws.writable) // true

    console.log(ws.path) // ~/wrote-35558.data

    await erase(ws)

    console.log(ws.closed) // true

})()



```



## `wrote.write(ws: Writable, data?: string|Readable): Promise.`



Pipe a `Readable` to the `Writable` stream and wait until it is finished, or end

 `Writable` with given data (pass `null` to end stream without any more data).



```js

const { write } = require('wrote')

const assert = require('assert')

const { Writable } = require('stream')



const testString = 'hello world'

const buffer = Buffer.from(testString)

const allRawData = []

const ws = new Writable({

    write(chunk, encoding, next) {

        allRawData.push(chunk)

        next()

    },

});



(async () => {

    await write(ws, buffer)

    console.log(allRawData.map(d => String(d))) // [ 'hello world' ]

    assert.deepEqual(allRawData, [

        buffer,

    ])

})()

```



## `wrote.ensurePath(filePath: string): Promise`



Create all required directories for the filepath to exist. If a directory on the way is

non-executable, the Promise will be rejected. Resolves with the filepath.



```js

const { ensurePath } = require('wrote')

const { resolve } = require('path');



(async () => {

    const path = 'path/to/temp/file.data'

    const res = await ensurePath(path)

    console.log(res) // path/to/temp/file.data, path/to/temp is created in your cwd



    const absolutePath = resolve(process.cwd(), 'path/to/temp/file.data')

    const res2 = await ensurePath(absolutePath)

    console.log(res2) // $(pwd)/path/to/temp/file.data

})()

```



## `wrote.read(path: string, { binary?: boolean }): Promise.`



Read a file fully. Returns a Promise resolved with the file contents, and

rejects if path is not a string or file not found (`ENOENT`).



```js

const { read } = require('wrote');



(async () => {

    const res = await read(__filename)

    console.log(res)

})()

```



`examples/read.js`: _this program will print the contents of itself_



Pass `{ binary: true }` options to read as a `Buffer`:



```js

const { read } = require('wrote');



(async () => {

    const buffer = await read(__filename, { binary: true })

    console.log(buffer) // // 

})()

```



## `wrote.readJSON(path: string): Promise.`



Read a json file and parse its contents.



```js

const { readJSON } = require('wrote');



(async () => {

    const res = await read('path/to/file.json')

    console.log(res)

})()

```



## `wrote.writeJSON(path: string, object: object, { replacer?: function, space?: string|number }): Promise`



Serialise an object with `JSON.stringify` and write it to a file. Pass `space`

and `replacer` in the options object.



```js

const { writeJSON } = require('wrote');



(async () => {

    const object = {

        test: 'data',

        date: new Date(),

    }

    await writeJSON('path/to/file.json', object, {

        space: 2,

        // replacer: () => {}

    })

})()

```



## `wrote.readDir(dirPath: string, recursive=: boolean): Promise`



Read a directory, and return contents of contained files.



For example, the following directory structure:



```fs

directory

 - subdirectory

    - subdirFileA.txt

    ` subdirFileB.txt

 - fileA.txt

 - fileB.txt

 ` fileC.txt

```



can be read either shallowly (by default):



```js

const { readDir } = require('wrote')

const path = require('path')



const dirPath = path.join(__dirname, 'directory');



(async () => {

    const res = await readDir(dirPath)

    console.log(res)

    // { 'fileA.txt': 'fileA\n',

    //   'fileB.txt': 'fileB\n',

    //   'fileC.txt': 'fileC\n' }

})()

```



or recursively:



```js

(async () => {

    const res = await readDir(dirPath, true)

    console.log(res)

    // { 'fileA.txt': 'fileA\n',

    //   'fileB.txt': 'fileB\n',

    //   'fileC.txt': 'fileC\n',

    //   subdirectory:

    //    { 'subdirFileA.txt': 'subdirFileA\n',

    //      'subdirFileB.txt': 'subdirFileB\n' } }

})()

```



## `wrote.readDirStructure(dirPath: string): Promise`



Get the full structure of the directory recursively. An array of either

file names as strings, or an object representing all directories of the

current one, with keys being their names, and values being arrays similar

to the root one.



```js

const path = require('path')

const { readDirStructure } = require('..')



const DIR_PATH = path.join(__dirname, '../test/fixtures/directory');



/**

 * Read directory's structure.

 */



(async () => {

    const res = await readDirStructure(DIR_PATH)

    console.log(JSON.stringify(res, null, 2))

})()

```



```fs

{

  "type": "Directory",

  "content": {

    "subdirectory-ln": {

      "type": "SymbolicLink"

    },

    "test-ln.data": {

      "type": "SymbolicLink"

    },

    "test.data": {

      "type": "File"

    },

    "subdirectory": {

      "type": "Directory",

      "content": {

        "file.data": {

          "type": "File"

        },

        "file2.data": {

          "type": "File"

        }

      }

    },

    "subdirectory2": {

      "type": "Directory",

      "content": {

        "file3.data": {

          "type": "File"

        },

        "subsubdir": {

          "type": "Directory",

          "content": {

            "file4.py": {

              "type": "File"

            }

          }

        },

        "subsubdir2": {

          "type": "Directory",

          "content": {}

        }

      }

    }

  }

}

```



## todo



- `eraseDir` to rm -rf

- `cloneFile` to clone a single file

- `write` with string as path

- `erase` with string as path

- `clone` with permissions

- pass options to `fs.createWriteStream` in `wrote.createWritable`



---



Licence: MIT



*(c) [Sobesednik-Media](https://sobesednik.media) 2017*