source: trip-planner-front/node_modules/npm-packlist/README.md@ 76712b2

# npm-packlist

[![Build Status](https://travis-ci.com/npm/npm-packlist.svg?token=hHeDp9pQmz9kvsgRNVHy&branch=master)](https://travis-ci.com/npm/npm-packlist)

Get a list of the files to add from a folder into an npm package.

These can be handed to [tar](http://npm.im/tar) like so to make an npm
package tarball:

```js
const packlist = require('npm-packlist')
const tar = require('tar')
const packageDir = '/path/to/package'
const packageTarball = '/path/to/package.tgz'

packlist({ path: packageDir })
  .then(files => tar.create({
    prefix: 'package/',
    cwd: packageDir,
    file: packageTarball,
    gzip: true
  }, files))
  .then(_ => {
    // tarball has been created, continue with your day
  })
```

This uses the following rules:

1. If a `package.json` file is found, and it has a `files` list,
   then ignore everything that isn't in `files`.  Always include the
   readme, license, notice, changes, changelog, and history files, if
   they exist, and the package.json file itself.
2. If there's no `package.json` file (or it has no `files` list), and
   there is a `.npmignore` file, then ignore all the files in the
   `.npmignore` file.
3. If there's no `package.json` with a `files` list, and there's no
   `.npmignore` file, but there is a `.gitignore` file, then ignore
   all the files in the `.gitignore` file.
4. Everything in the root `node_modules` is ignored, unless it's a
   bundled dependency.  If it IS a bundled dependency, and it's a
   symbolic link, then the target of the link is included, not the
   symlink itself.
4. Unless they're explicitly included (by being in a `files` list, or
   a `!negated` rule in a relevant `.npmignore` or `.gitignore`),
   always ignore certain common cruft files:

    1. .npmignore and .gitignore files (their effect is in the package
       already, there's no need to include them in the package)
    2. editor junk like `.*.swp`, `._*` and `.*.orig` files
    3. `.npmrc` files (these may contain private configs)
    4. The `node_modules/.bin` folder
    5. Waf and gyp cruft like `/build/config.gypi` and `.lock-wscript`
    6. Darwin's `.DS_Store` files because wtf are those even
    7. `npm-debug.log` files at the root of a project

    You can explicitly re-include any of these with a `files` list in
    `package.json` or a negated ignore file rule.

Only the `package.json` file in the very root of the project is ever
inspected for a `files` list.  Below the top level of the root package,
`package.json` is treated as just another file, and no package-specific
semantics are applied.

### Interaction between `package.json` and `.npmignore` rules

For simplicity, it is best to use _either_ a `files` list in `package.json`
_or_ a `.npmignore` file, and not both.  If you only use one of these
methods, you can skip this documentation section.

The `files` list in `package.json` is used to direct the exploration of the
tree.  In other words, that's all the walker will ever look at when
exploring that level.

In some cases this can lead to a `.npmignore` file being ignored.  If a
_directory_ is listed in `files`, then any rules in a root or nested
`.npmignore` files will be honored.

For example, with this package.json:

```json
{
  "files": [ "dir" ]
}
```

a `.npmignore` file at `dir/.npmignore` (and any subsequent
sub-directories) will be honored.  However, a `.npmignore` at the root
level will be skipped.

Conversely, with this package.json:

```
{
  "files": ["dir/subdir"]
}
```

a `.npmignore` file at `dir/.npmignore` will not be honored.

Any specific file matched by a glob or filename in the package.json `files`
list will be included, and cannot be excluded by any `.npmignore` files in
nested directories, or by a `.npmignore` file in the root package
directory, unless that root `.npmignore` file is also in the `files` list.

The previous (v1) implementation used in npm 6 and below treated
`package.json` as a special sort of "reverse ignore" file.  That is, it was
parsed and handled as if it was a `.npmignore` file with `!` prepended to
all of the globs in the `files` list.  In order to include children of a
directory listed in `files`, they would _also_ have `/**` appended to them.

This is tricky to explain, but is a significant improvement over the
previous (v1) implementation used in npm 6 and below, with the following
beneficial properties:

- If you have `{"files":["lib"]}` in `package.json`, then the walker will
  still ignore files such as `lib/.DS_Store` and `lib/.foo.swp`.  The
  previous implementation would include these files, as they'd be matched
  by the computed `!lib/**` ignore rule.
- If you have `{"files":["lib/a.js","lib/b.js"]}` in `package.json`, and a
  `lib/.npmignore` containing `a.js`, then the walker will still include
  the two files indicated in `package.json`, and ignore the
  `lib/.npmignore` file.  The previous implementation would mark these
  files for inclusion, but then _exclude_ them when it came to the nested
  `.npmignore` file.  (Ignore file semantics dictate that a "closer" ignore
  file always takes precedence.)
- A file in `lib/pkg-template/package.json` will be included, and its
  `files` list will not have any bearing on other files being included or
  skipped.  When treating `package.json` as just Yet Another ignore file,
  this was not the case, leading to difficulty for modules that aim to
  initialize a project.

In general, this walk should work as a reasonable developer would expect.
Matching human expectation is tricky business, and if you find cases where
it violates those expectations, [please let us
know](https://github.com/npm/npm-packlist/issues).

## API

Same API as [ignore-walk](http://npm.im/ignore-walk), just hard-coded
file list and rule sets.

The `Walker` and `WalkerSync` classes take a `bundled` argument, which
is a list of package names to include from node_modules.  When calling
the top-level `packlist()` and `packlist.sync()` functions, this
module calls into `npm-bundled` directly.