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- # cosmiconfig
-
- [![Build Status](https://img.shields.io/travis/davidtheclark/cosmiconfig/master.svg?label=unix%20build)](https://travis-ci.org/davidtheclark/cosmiconfig) [![Build status](https://img.shields.io/appveyor/ci/davidtheclark/cosmiconfig/master.svg?label=windows%20build)](https://ci.appveyor.com/project/davidtheclark/cosmiconfig/branch/master)
- [![codecov](https://codecov.io/gh/davidtheclark/cosmiconfig/branch/master/graph/badge.svg)](https://codecov.io/gh/davidtheclark/cosmiconfig)
-
- Cosmiconfig searches for and loads configuration for your program.
-
- It features smart defaults based on conventional expectations in the JavaScript ecosystem.
- But it's also flexible enough to search wherever you'd like to search, and load whatever you'd like to load.
-
- By default, Cosmiconfig will start where you tell it to start and search up the directory tree for the following:
-
- - a `package.json` property
- - a JSON or YAML, extensionless "rc file"
- - an "rc file" with the extensions `.json`, `.yaml`, `.yml`, or `.js`.
- - a `.config.js` CommonJS module
-
- For example, if your module's name is "soursocks", cosmiconfig will search up the directory tree for configuration in the following places:
-
- - a `soursocks` property in `package.json`
- - a `.soursocksrc` file in JSON or YAML format
- - a `.soursocksrc.json` file
- - a `.soursocksrc.yaml`, `.soursocksrc.yml`, or `.soursocksrc.js` file
- - a `soursocks.config.js` file exporting a JS object
-
- Cosmiconfig continues to search up the directory tree, checking each of these places in each directory, until it finds some acceptable configuration (or hits the home directory).
-
- 👀 **Looking for the v4 docs?**
- v5 involves significant revisions to Cosmiconfig's API, allowing for much greater flexibility and clarifying some things.
- If you have trouble switching from v4 to v5, please file an issue.
- If you are still using v4, those v4 docs are available [in the `4.0.0` tag](https://github.com/davidtheclark/cosmiconfig/tree/4.0.0).
-
- ## Table of contents
-
- - [Installation](#installation)
- - [Usage](#usage)
- - [Result](#result)
- - [cosmiconfig()](#cosmiconfig-1)
- - [moduleName](#modulename)
- - [explorer.search()](#explorersearch)
- - [searchFrom](#searchfrom)
- - [explorer.searchSync()](#explorersearchsync)
- - [explorer.load()](#explorerload)
- - [explorer.loadSync()](#explorerloadsync)
- - [explorer.clearLoadCache()](#explorerclearloadcache)
- - [explorer.clearSearchCache()](#explorerclearsearchcache)
- - [explorer.clearCaches()](#explorerclearcaches)
- - [cosmiconfigOptions](#cosmiconfigoptions)
- - [searchPlaces](#searchplaces)
- - [loaders](#loaders)
- - [packageProp](#packageprop)
- - [stopDir](#stopdir)
- - [cache](#cache)
- - [transform](#transform)
- - [ignoreEmptySearchPlaces](#ignoreemptysearchplaces)
- - [Caching](#caching)
- - [Differences from rc](#differences-from-rc)
- - [Contributing & Development](#contributing--development)
-
- ## Installation
-
- ```
- npm install cosmiconfig
- ```
-
- Tested in Node 4+.
-
- ## Usage
-
- Create a Cosmiconfig explorer, then either `search` for or directly `load` a configuration file.
-
- ```js
- const cosmiconfig = require('cosmiconfig');
- // ...
- const explorer = cosmiconfig(moduleName);
-
- // Search for a configuration by walking up directories.
- // See documentation for search, below.
- explorer.search()
- .then((result) => {
- // result.config is the parsed configuration object.
- // result.filepath is the path to the config file that was found.
- // result.isEmpty is true if there was nothing to parse in the config file.
- })
- .catch((error) => {
- // Do something constructive.
- });
-
- // Load a configuration directly when you know where it should be.
- // The result object is the same as for search.
- // See documentation for load, below.
- explorer.load(pathToConfig).then(..);
-
- // You can also search and load synchronously.
- const searchedFor = explorer.searchSync();
- const loaded = explorer.loadSync(pathToConfig);
- ```
-
- ## Result
-
- The result object you get from `search` or `load` has the following properties:
-
- - **config:** The parsed configuration object. `undefined` if the file is empty.
- - **filepath:** The path to the configuration file that was found.
- - **isEmpty:** `true` if the configuration file is empty. This property will not be present if the configuration file is not empty.
-
- ## cosmiconfig()
-
- ```js
- const explorer = cosmiconfig(moduleName[, cosmiconfigOptions])
- ```
-
- Creates a cosmiconfig instance ("explorer") configured according to the arguments, and initializes its caches.
-
- ### moduleName
-
- Type: `string`. **Required.**
-
- Your module name. This is used to create the default [`searchPlaces`] and [`packageProp`].
-
- **[`cosmiconfigOptions`] are documented below.**
- You may not need them, and should first read about the functions you'll use.
-
- ## explorer.search()
-
- ```js
- explorer.search([searchFrom]).then(result => {..})
- ```
-
- Searches for a configuration file. Returns a Promise that resolves with a [result] or with `null`, if no configuration file is found.
-
- You can do the same thing synchronously with [`searchSync()`].
-
- Let's say your module name is `goldengrahams` so you initialized with `const explorer = cosmiconfig('goldengrahams');`.
- Here's how your default [`search()`] will work:
-
- - Starting from `process.cwd()` (or some other directory defined by the `searchFrom` argument to [`search()`]), look for configuration objects in the following places:
- 1. A `goldengrahams` property in a `package.json` file.
- 2. A `.goldengrahamsrc` file with JSON or YAML syntax.
- 3. A `.goldengrahamsrc.json` file.
- 4. A `.goldengrahamsrc.yaml`, `.goldengrahamsrc.yml`, or `.goldengrahamsrc.js` file.
- 5. A `goldengrahams.config.js` JS file exporting the object.
- - If none of those searches reveal a configuration object, move up one directory level and try again.
- So the search continues in `./`, `../`, `../../`, `../../../`, etc., checking the same places in each directory.
- - Continue searching until arriving at your home directory (or some other directory defined by the cosmiconfig option [`stopDir`]).
- - If at any point a parseable configuration is found, the [`search()`] Promise resolves with its [result] \(or, with [`searchSync()`], the [result] is returned).
- - If no configuration object is found, the [`search()`] Promise resolves with `null` (or, with [`searchSync()`], `null` is returned).
- - If a configuration object is found *but is malformed* (causing a parsing error), the [`search()`] Promise rejects with that error (so you should `.catch()` it). (Or, with [`searchSync()`], the error is thrown.)
-
- **If you know exactly where your configuration file should be, you can use [`load()`], instead.**
-
- **The search process is highly customizable.**
- Use the cosmiconfig options [`searchPlaces`] and [`loaders`] to precisely define where you want to look for configurations and how you want to load them.
-
- ### searchFrom
-
- Type: `string`.
- Default: `process.cwd()`.
-
- A filename.
- [`search()`] will start its search here.
-
- If the value is a directory, that's where the search starts.
- If it's a file, the search starts in that file's directory.
-
- ## explorer.searchSync()
-
- ```js
- const result = explorer.searchSync([searchFrom]);
- ```
-
- Synchronous version of [`search()`].
-
- Returns a [result] or `null`.
-
- ## explorer.load()
-
- ```js
- explorer.load(loadPath).then(result => {..})
- ```
-
- Loads a configuration file. Returns a Promise that resolves with a [result] or rejects with an error (if the file does not exist or cannot be loaded).
-
- Use `load` if you already know where the configuration file is and you just need to load it.
-
- ```js
- explorer.load('load/this/file.json'); // Tries to load load/this/file.json.
- ```
-
- If you load a `package.json` file, the result will be derived from whatever property is specified as your [`packageProp`].
-
- ## explorer.loadSync()
-
- ```js
- const result = explorer.loadSync(loadPath);
- ```
-
- Synchronous version of [`load()`].
-
- Returns a [result].
-
- ## explorer.clearLoadCache()
-
- Clears the cache used in [`load()`].
-
- ## explorer.clearSearchCache()
-
- Clears the cache used in [`search()`].
-
- ## explorer.clearCaches()
-
- Performs both [`clearLoadCache()`] and [`clearSearchCache()`].
-
- ## cosmiconfigOptions
-
- Type: `Object`.
-
- Possible options are documented below.
-
- ### searchPlaces
-
- Type: `Array<string>`.
- Default: See below.
-
- An array of places that [`search()`] will check in each directory as it moves up the directory tree.
- Each place is relative to the directory being searched, and the places are checked in the specified order.
-
- **Default `searchPlaces`:**
-
- ```js
- [
- 'package.json',
- `.${moduleName}rc`,
- `.${moduleName}rc.json`,
- `.${moduleName}rc.yaml`,
- `.${moduleName}rc.yml`,
- `.${moduleName}rc.js`,
- `${moduleName}.config.js`,
- ]
- ```
-
- Create your own array to search more, fewer, or altogether different places.
-
- Every item in `searchPlaces` needs to have a loader in [`loaders`] that corresponds to its extension.
- (Common extensions are covered by default loaders.)
- Read more about [`loaders`] below.
-
- `package.json` is a special value: When it is included in `searchPlaces`, Cosmiconfig will always parse it as JSON and load a property within it, not the whole file.
- That property is defined with the [`packageProp`] option, and defaults to your module name.
-
- Examples, with a module named `porgy`:
-
- ```js
- // Disallow extensions on rc files:
- [
- 'package.json',
- '.porgyrc',
- 'porgy.config.js'
- ]
-
- // ESLint searches for configuration in these places:
- [
- '.eslintrc.js',
- '.eslintrc.yaml',
- '.eslintrc.yml',
- '.eslintrc.json',
- '.eslintrc',
- 'package.json'
- ]
-
- // Babel looks in fewer places:
- [
- 'package.json',
- '.babelrc'
- ]
-
- // Maybe you want to look for a wide variety of JS flavors:
- [
- 'porgy.config.js',
- 'porgy.config.mjs',
- 'porgy.config.ts',
- 'porgy.config.coffee'
- ]
- // ^^ You will need to designate custom loaders to tell
- // Cosmiconfig how to handle these special JS flavors.
-
- // Look within a .config/ subdirectory of every searched directory:
- [
- 'package.json',
- '.porgyrc',
- '.config/.porgyrc',
- '.porgyrc.json',
- '.config/.porgyrc.json'
- ]
- ```
-
- ### loaders
-
- Type: `Object`.
- Default: See below.
-
- An object that maps extensions to the loader functions responsible for loading and parsing files with those extensions.
-
- Cosmiconfig exposes its default loaders for `.js`, `.json`, and `.yaml` as `cosmiconfig.loadJs`, `cosmiconfig.loadJson`, and `cosmiconfig.loadYaml`, respectively.
-
- **Default `loaders`:**
-
- ```js
- {
- '.json': cosmiconfig.loadJson,
- '.yaml': cosmiconfig.loadYaml,
- '.yml': cosmiconfig.loadYaml,
- '.js': cosmiconfig.loadJs,
- noExt: cosmiconfig.loadYaml
- }
- ```
-
- (YAML is a superset of JSON; which means YAML parsers can parse JSON; which is how extensionless files can be either YAML *or* JSON with only one parser.)
-
- **If you provide a `loaders` object, your object will be *merged* with the defaults.**
- So you can override one or two without having to override them all.
-
- **Keys in `loaders`** are extensions (starting with a period), or `noExt` to specify the loader for files *without* extensions, like `.soursocksrc`.
-
- **Values in `loaders`** are either a loader function (described below) or an object with `sync` and/or `async` properties, whose values are loader functions.
-
- **The most common use case for custom loaders value is to load extensionless `rc` files as strict JSON**, instead of JSON *or* YAML (the default).
- To accomplish that, provide the following `loaders` value:
-
- ```js
- {
- noExt: cosmiconfig.loadJson
- }
- ```
-
- If you want to load files that are not handled by the loader functions Cosmiconfig exposes, you can write a custom loader function or use one from NPM if it exists.
-
- **Third-party loaders:**
-
- - [@endemolshinegroup/cosmiconfig-typescript-loader](https://github.com/EndemolShineGroup/cosmiconfig-typescript-loader)
-
- **Use cases for custom loader function:**
-
- - Allow configuration syntaxes that aren't handled by Cosmiconfig's defaults, like JSON5, INI, or XML.
- - Allow ES2015 modules from `.mjs` configuration files.
- - Parse JS files with Babel before deriving the configuration.
-
- **Custom loader functions** have the following signature:
-
- ```js
- // Sync
- (filepath: string, content: string) => Object | null
-
- // Async
- (filepath: string, content: string) => Object | null | Promise<Object | null>
- ```
-
- Cosmiconfig reads the file when it checks whether the file exists, so it will provide you with both the file's path and its content.
- Do whatever you need to, and return either a configuration object or `null` (or, for async-only loaders, a Promise that resolves with one of those).
- `null` indicates that no real configuration was found and the search should continue.
-
- It's easiest if you make your custom loader function synchronous.
- Then it can be used regardless of whether you end up calling [`search()`] or [`searchSync()`], [`load()`] or [`loadSync()`].
- If you want or need to provide an async-only loader, you can do so by making the value of `loaders` an object with an `async` property whose value is the async loader.
- You can also add a `sync` property to designate a sync loader, if you want to use both async and sync search and load functions.
-
- A few things to note:
-
- - If you use a custom loader, be aware of whether it's sync or async and how that aligned with your usage of sync or async search and load functions.
- - **Special JS syntax can also be handled by using a `require` hook**, because `cosmiconfig.loadJs` just uses `require`.
- Whether you use custom loaders or a `require` hook is up to you.
-
- Examples:
-
- ```js
- // Allow JSON5 syntax:
- {
- '.json': json5Loader
- }
-
- // Allow XML, and treat sync and async separately:
- {
- '.xml': { async: asyncXmlLoader, sync: syncXmlLoader }
- }
-
- // Allow a special configuration syntax of your own creation:
- {
- '.special': specialLoader
- }
-
- // Allow many flavors of JS, using custom loaders:
- {
- '.mjs': esmLoader,
- '.ts': typeScriptLoader,
- '.coffee': coffeeScriptLoader
- }
-
- // Allow many flavors of JS but rely on require hooks:
- {
- '.mjs': cosmiconfig.loadJs,
- '.ts': cosmiconfig.loadJs,
- '.coffee': cosmiconfig.loadJs
- }
- ```
-
- ### packageProp
-
- Type: `string | Array<string>`.
- Default: `` `${moduleName}` ``.
-
- Name of the property in `package.json` to look for.
-
- Use a period-delimited string or an array of strings to describe a path to nested properties.
-
- For example, the value `'configs.myPackage'` or `['configs', 'myPackage']` will get you the `"myPackage"` value in a `package.json` like this:
-
- ```json
- {
- "configs": {
- "myPackage": {..}
- }
- }
- ```
-
- If nested property names within the path include periods, you need to use an array of strings. For example, the value `['configs', 'foo.bar', 'baz']` will get you the `"baz"` value in a `package.json` like this:
-
- ```json
- {
- "configs": {
- "foo.bar": {
- "baz": {..}
- }
- }
- }
- ```
-
- If a string includes period but corresponds to a top-level property name, it will not be interpreted as a period-delimited path. For example, the value `'one.two'` will get you the `"three"` value in a `package.json` like this:
-
- ```json
- {
- "one.two": "three",
- "one": {
- "two": "four"
- }
- }
- ```
-
- ### stopDir
-
- Type: `string`.
- Default: Absolute path to your home directory.
-
- Directory where the search will stop.
-
- ### cache
-
- Type: `boolean`.
- Default: `true`.
-
- If `false`, no caches will be used.
- Read more about ["Caching"](#caching) below.
-
- ### transform
-
- Type: `(Result) => Promise<Result> | Result`.
-
- A function that transforms the parsed configuration. Receives the [result].
-
- If using [`search()`] or [`load()`] \(which are async), the transform function can return the transformed result or return a Promise that resolves with the transformed result.
- If using [`searchSync()`] or [`loadSync()`], the function must be synchronous and return the transformed result.
-
- The reason you might use this option — instead of simply applying your transform function some other way — is that *the transformed result will be cached*. If your transformation involves additional filesystem I/O or other potentially slow processing, you can use this option to avoid repeating those steps every time a given configuration is searched or loaded.
-
- ### ignoreEmptySearchPlaces
-
- Type: `boolean`.
- Default: `true`.
-
- By default, if [`search()`] encounters an empty file (containing nothing but whitespace) in one of the [`searchPlaces`], it will ignore the empty file and move on.
- If you'd like to load empty configuration files, instead, set this option to `false`.
-
- Why might you want to load empty configuration files?
- If you want to throw an error, or if an empty configuration file means something to your program.
-
- ## Caching
-
- As of v2, cosmiconfig uses caching to reduce the need for repetitious reading of the filesystem or expensive transforms. Every new cosmiconfig instance (created with `cosmiconfig()`) has its own caches.
-
- To avoid or work around caching, you can do the following:
-
- - Set the `cosmiconfig` option [`cache`] to `false`.
- - Use the cache-clearing methods [`clearLoadCache()`], [`clearSearchCache()`], and [`clearCaches()`].
- - Create separate instances of cosmiconfig (separate "explorers").
-
- ## Differences from [rc](https://github.com/dominictarr/rc)
-
- [rc](https://github.com/dominictarr/rc) serves its focused purpose well. cosmiconfig differs in a few key ways — making it more useful for some projects, less useful for others:
-
- - Looks for configuration in some different places: in a `package.json` property, an rc file, a `.config.js` file, and rc files with extensions.
- - Built-in support for JSON, YAML, and CommonJS formats.
- - Stops at the first configuration found, instead of finding all that can be found up the directory tree and merging them automatically.
- - Options.
- - Asynchronous by default (though can be run synchronously).
-
- ## Contributing & Development
-
- Please note that this project is released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md). By participating in this project you agree to abide by its terms.
-
- And please do participate!
-
- [result]: #result
-
- [`load()`]: #explorerload
-
- [`loadsync()`]: #explorerloadsync
-
- [`search()`]: #explorersearch
-
- [`searchsync()`]: #explorersearchsync
-
- [`clearloadcache()`]: #explorerclearloadcache
-
- [`clearsearchcache()`]: #explorerclearsearchcache
-
- [`clearcaches()`]: #explorerclearcaches
-
- [`packageprop`]: #packageprop
-
- [`cache`]: #cache
-
- [`stopdir`]: #stopdir
-
- [`searchplaces`]: #searchplaces
-
- [`loaders`]: #loaders
-
- [`cosmiconfigoptions`]: #cosmiconfigoptions
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