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# ignore

`ignore` is a manager and filter which implemented in pure JavaScript according to the .gitignore [spec](http://git-scm.com/docs/gitignore).

Pay attention that [`minimatch`](https://www.npmjs.org/package/minimatch) does not work in the gitignore way. To filter filenames according to .gitignore file, I recommend this module.

##### Tested on

- Linux + Node: `0.8` - `5.x`
- Windows + Node: `0.10` - `5.x`, node < `0.10` is not tested due to the lack of support of appveyor.

## Table Of Main Contents

- [Usage](#usage)
- [Guide for 2.x -> 3.x](#upgrade-2x---3x)
- [Contributing](#contributing)

## Usage

```js
const ignore = require('ignore')
let ig = ignore().add(['.abc/*', '!.abc/d/'])
```

### Filter the given paths

```js
let paths = [
  '.abc/a.js',    // filtered out
  '.abc/d/e.js'   // included
]

ig.filter(paths)  // ['.abc/d/e.js']
```

### As the filter function

```js
paths.filter(ig.createFilter()); // ['.abc/d/e.js']
```

### Win32 paths will be handled

```js
ig.filter(['.abc\\a.js', '.abc\\d\\e.js'])
// if the code above runs on windows, the result will be
// ['.abc\\d\\e.js']
```

## Why another ignore?

1. `ignore` is a standalone module, and is much simpler so that it could easy work with other programs, unlike [isaacs](https://npmjs.org/~isaacs)'s [fstream-ignore](https://npmjs.org/package/fstream-ignore) which must work with the modules of the fstream family.

2. `ignore` only contains utility methods to filter paths according to the specified ignore rules, so
  - `ignore` never try to find out ignore rules by traversing directories or fetching from git configurations.
  - `ignore` don't cares about sub-modules of git projects.

3. Exactly according to [gitignore man page](http://git-scm.com/docs/gitignore), fixes some known matching issues of fstream-ignore, such as:
  - '`/*.js`' should only match '`a.js`', but not '`abc/a.js`'.
  - '`**/foo`' should match '`foo`' anywhere.
  - prevent re-including a file if a parent directory of that file is excluded.
  - handle trailing whitespaces:
    - `'a '`(one space) should not match `'a  '`(two spaces).
    - `'a \ '` matches `'a  '`

## Methods

### .add(pattern)
### .add(patterns)

- pattern `String|Ignore` An ignore pattern string, or the `Ignore` instance
- patterns `Array.<pattern>` Array of ignore patterns.

Adds a rule or several rules to the current manager.

Returns `this`

Notice that a line starting with `'#'`(hash) is treated as a comment. Put a backslash (`'\'`) in front of the first hash for patterns that begin with a hash, if you want to ignore a file with a hash at the beginning of the filename.

```js
ignore().add('#abc').filter(['#abc'])   // ['#abc']
ignore().add('\#abc').filter(['#abc'])  // []
```

`pattern` could either be a line of ignore pattern or a string of multiple ignore patterns, which means we could just `ignore().add()` the content of a ignore file:

```js
ignore().add(fs.readFileSync(filenameOfGitignore).toString()).filter(filenames)
```

`pattern` could also be an `ignore` instance, so that we could easily inherit the rules of another `Ignore` instance.

### <strike>.addIgnoreFile(path)</strike>

REMOVED in `3.x` for now.

To upgrade `ignore@2.x` up to `3.x`, use

```js
const fs = require('fs')

if (fs.existsSync(filename)) {
  ignore().add(fs.readFileSync(filename).toString())
}
```

instead.


### .filter(paths)

Filters the given array of pathnames, and returns the filtered array.

- paths `Array.<path>` The array of paths to be filtered.

*NOTICE* that each `path` here should be a relative path to the root of your repository. Suppose the dir structure is:

```
/path/to/your/repo
    |-- a
    |   |-- a.js
    |
    |-- .b
    |
    |-- .c
         |-- .DS_store
```

Then the `paths` might be like this:

```js
[
  'a/a.js'
  '.b',
  '.c/.DS_store'
]
```

Usually, you could use [`glob`](http://npmjs.org/package/glob) with `option.mark = true` to fetch the structure of the current directory:

```js
const glob = require('glob')

glob('**', {
  // Adds a / character to directory matches.
  mark: true
}, (err, files) => {
  if (err) {
    return console.error(err)
  }

  let filtered = ignore().add(patterns).filter(files)
  console.log(filtered)
})
```

### .createFilter()

Creates a filter function which could filter an array of paths with `Array.prototype.filter`.

Returns `function(path)` the filter function.

****

## Upgrade 2.x -> 3.x

- All `options` of 2.x are unnecessary and removed, so just remove them.
- `ignore()` instance is no longer an [`EventEmitter`](nodejs.org/api/events.html), and all events are unnecessary and removed.
- `.addIgnoreFile()` is removed, see the [.addIgnoreFile](#addignorefilepath) section for details.

****

## Contributing

The code of `node-ignore` is based on es6 and babel, but babel and its preset is not included in the `dependencies` field of package.json, so that the installation process of test cases will not fail in older versions of node.

So use `bash install.sh` to install dependencies and `bash test.sh` to run test cases in your local machine.

#### Collaborators

- [SamyPesse](https://github.com/SamyPesse) *Samy Pessé*
- [azproduction](https://github.com/azproduction) *Mikhail Davydov*
- [TrySound](https://github.com/TrySound) *Bogdan Chadkin*
- [JanMattner](https://github.com/JanMattner) *Jan Mattner*
