# sanitize-filename-ts

Sanitize a string to be safe for use as a filename by removing directory
paths and invalid characters. This package is a fork of sanitize-filename, updated and rewritten in
Typescript.

## Install

[npm: _sanitize-filename-ts_](https://www.npmjs.com/package/sanitize-filename-ts)

```
npm install sanitize-filename-ts
```

## Example

```js
import { sanitize } from "sanitize-filename-ts";

// Some string that may be unsafe or invalid as a filename
var UNSAFE_USER_INPUT = "~/.\u0000ssh/authorized_keys";

// Sanitize the string to be safe for use as a filename.
var filename = sanitize(UNSAFE_USER_INPUT);
// -> "~.sshauthorized_keys"
```

## Details

_sanitize-filename-ts_ removes the following:

- [Control characters][] (`0x00`–`0x1f` and `0x80`–`0x9f`)
- [Reserved characters][] (`/`, `?`, `<`, `>`, `\`, `:`, `*`, `|`, and
  `"`)
- Unix reserved filenames (`.` and `..`)
- Trailing periods and spaces ([for Windows][windows trailing])
- Windows reserved filenames (`CON`, `PRN`, `AUX`, `NUL`, `COM1`,
  `COM2`, `COM3`, `COM4`, `COM5`, `COM6`, `COM7`, `COM8`, `COM9`,
  `LPT1`, `LPT2`, `LPT3`, `LPT4`, `LPT5`, `LPT6`, `LPT7`, `LPT8`, and
  `LPT9`)

[control characters]: https://en.wikipedia.org/wiki/C0_and_C1_control_codes
[reserved characters]: https://kb.acronis.com/content/39790
[windows trailing]: https://msdn.microsoft.com/en-us/library/aa365247(v=vs.85).aspx#Naming_Conventions

The resulting string is truncated to [255 bytes in length][255]. The
string will not contain any directory paths and will be safe to use as a
filename.

[255]: http://unix.stackexchange.com/questions/32795/what-is-the-maximum-allowed-filename-and-folder-size-with-ecryptfs

### Empty String `""` Result

An empty string `""` can be returned. For example:

```js
import { sanitize } from "sanitize-filename-ts";
sanitize("..");
// -> ""
```

### Non-unique Filenames

Two different inputs can return the same value. For example:

```js
import { sanitize } from "sanitize-filename-ts";
sanitize("file?");
// -> "file"
sanitize("*file*");
// -> "file"
```

### File Systems

Sanitized filenames will be safe for use on modern Windows, OS X, and
Unix file systems (`NTFS`, `ext`, etc.).

[`FAT` 8.3 filenames][8.3] are not supported.

[8.3]: https://en.wikipedia.org/wiki/8.3_filename

#### Test Your File System

The test program will use various strings (including the [Big List of
Naughty Strings][blns]) to create files in the working directory. Run
`npm test` to run tests against your file system.

[blns]: https://github.com/minimaxir/big-list-of-naughty-strings

## API

### `sanitize(inputString, [options])`

Sanitize `inputString` by removing or replacing invalid characters.

Options:

- `options.replacement`: _optional, string/function, default: `""`_. If passed
  as a string, it's used as the replacement for invalid characters. If passed as
  a function, the function will be called with the invalid characters and it's
  return value will be used as the replacement. See [`String.prototype.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace)
  for more info.