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README.md

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+
+# Node Release Lines
+
+Introspection API for Node.js release metadata. Provides information about release lines, their relative status along with details of each release.
+
+See [how release lines work][] for more context.
+
+>Currently optimized for offline mode. Release schedule has apis to support both online & offline mode.
+
+## Installation
+
+``` bash
+npm install node-release-lines
+```
+
+## Outline
+
+- [Terminology][]
+- [ReleaseLine][] _class_
+- [ReleaseLines][] extends `Array` _class_
+- [Release][] _class_
+- [Releases][] extends `Array` _class_
+- [Vulnerability][] _class_
+
+## Usage
+
+``` js
+const { ReleaseLines } = require('node-release-lines')
+
+const releases = ReleaseLines.load('2018-09-15') // state of release lines at a point in time
+
+if (releases.getLTS().length === 4 && // LTS release lines
+    releases.getEOL().length === 6 && // release lines that have reached EOL (end of life)
+    releases.getEOL().getModern().length === 4 && // "modern" EOL release lines
+    releases.getEOL().getLTS().length === 1) { // LTS release lines that are EOL
+  // examine supported release lines
+
+  releases.getSupported().forEach(line => {
+    let stats = line.getStats()
+    console.log({
+      version: line.version,
+      daysToEOL: stats.days.until.eol,
+      progress: `${stats.percent.total}%`,
+      state: {
+        lts: line.isLTS,
+        isCurrent: line.isCurrent,
+        isActive: line.isActive,
+        isMaintenance: line.isMaintenance
+      },
+      releases: {
+        total: line.releases.length,
+        safe: line.releases.getSafe().length,
+        latest: line.releases[0].version
+      }
+    })
+  })
+}
+```
+
+### Output
+
+``` js
+{ version: 'v6',
+  daysToEOL: 198,
+  progress: '81%',
+  state:
+   { lts: true,
+     isCurrent: false,
+     isActive: false,
+     isMaintenance: true },
+  releases: { total: 39, safe: 1, latest: 'v6.14.3' } }
+{ version: 'v8',
+  daysToEOL: 472,
+  progress: '50%',
+  state:
+   { lts: true,
+     isCurrent: false,
+     isActive: true,
+     isMaintenance: false },
+  releases: { total: 26, safe: 2, latest: 'v8.11.4' } }
+{ version: 'v10',
+  daysToEOL: 929,
+  progress: '13%',
+  state:
+   { lts: true,
+     isCurrent: true,
+     isActive: false,
+     isMaintenance: false },
+  releases: { total: 12, safe: 6, latest: 'v10.9.0' } }
+```
+
+# API
+
+<a name="terminology"></a>
+## Terminology
+
+- **EOL**: (end of life) - any `ReleaseLine` no longer supported and recieves no more updates.
+- **Supported**: any `ReleaseLine` that has been started and has not reached EOL.
+- **LTS**: any `ReleaseLine` that has an active LTS period in the lifecycle. 
+- **Active**: any `ReleaseLine` that is in LTS, excluding maintenance window.
+- **Maintenance**: any `ReleaseLine` that is in maintenance mode and has not reached EOL.
+- **Current**: any `ReleaseLine` that has been started, in active development, not in maintenance or LTS.
+- **Future**: any defined `ReleaseLine` that has yet to start.
+- **Modern**: any `ReleaseLine` that is `v1` or greater. This does not include io.js releases (any version from `v4` onwards).
+
+<a name="ReleaseLine"></a>
+## `ReleaseLine` _class_
+
+**Instance properties**:
+- **version**: `String`
+- **start**: `Date`
+- **end**: `Date`
+- **lts**: `Date` or `undefined`
+- **maintenance**: `Date` or `undefined`
+- **codename**: `String` or `undefined`
+- **releases**: `Releases` _see [Releases][] section_
+
+**Instance getters**:
+
+_[see terminology]_
+
+- **isEOL**: `Boolean`
+- **isSupported**: `Boolean`
+- **isLTS**: `Boolean`
+- **isActive**: `Boolean`
+- **inLTS**: `Boolean` alias for `isActive`
+- **isMaintenance**: `Boolean`
+- **isCurrent**: `Boolean`
+- **isFuture**: `Boolean`
+- **isModern**: `Boolean`
+- **notStarted**: `Boolean`
+
+### `setDate(date)`
+
+Changes the `date` for calculating stats in `getStats`
+
+**Params**:
+- **date**: Date instance (optional, defaults=`Date.now`)
+
+**Returns**: `this`
+
+### `getStats(precision)`
+
+**Params**:
+- **precision**: `Number` 
+
+Stats about the relative timeline of the release based on the current `setDate`.
+
+**Notes**:
+- `0` will be used for unknown values. For example `maintenance`, `lts` are not valid for some release.
+- If a value is negative `0` is returned instead. This is useful for a `ReleaseLine` that hasn't started.
+- returned stats object is not bound to `setDate`
+
+**Returns**:
+``` js
+{ days: { 
+    total: 1073, // total days release is supported
+    current: 160, // days in `current` mode
+    lts: 548, // days in `active` LTS
+    maintenance: 365, // days in maintenance
+    completed: { 
+        total: 144, 
+        current: 144, 
+        lts: 0, 
+        maintenance: 0 },
+    remaining: { 
+        total: 929, 
+        current: 16, 
+        lts: 548, 
+        maintenance: 365 },
+    until: { 
+        start: 0, // already started
+        lts: 16, 
+        maintenance: 564, 
+        eol: 929 } 
+    },
+  percent: { 
+      total: 13, // complete
+      current: 90, 
+      lts: 0, 
+      maintenance: 0 } 
+}
+```
+
+<a name="ReleaseLines"></a>
+## `ReleaseLines` extends `Array` _class_
+
+An array of `ReleaseLine` instances. Provides helper methods for updating, filtering and querying release lines.
+
+### `ReleaseLines.load(schedule, date)` _static_
+
+Hydrates a schedule. If a schedule is not defined then the internal cached copy is automatically used.
+
+**Params**:
+- **schedule**: an object of release lines (optional)
+    - **key**: version of the release
+    - **value**: `Object`
+        - **start**: `String` or `Date` (required)
+        - **endt**: `String` or `Date` (required)
+        - **lts**: `String` or `Date`
+        - **maintenance**: `String` or `Date`
+        - **codename**: `String` 
+- **date**: Date instance (optional, defaults=`Date.now`)
+
+**Returns**: `ReleaseLines` instance
+
+### `ReleaseLines.fetch(date)` _static_
+
+**Params**:
+- **date**: Date instance (optional, defaults=`Date.now`)
+
+**Returns**: `Promise` - resolves to `ReleaseLines` instance
+
+### `ReleaseLines.scheduleUrl` (string) _static_
+
+The url to the offical [release schedule][]. 
+
+### `get(version)`
+
+**Params**:
+- **version**: a release line name (example: `v10`)
+
+**Returns**: `ReleaseLine` or `undefined`
+
+### `setDate(date)`
+
+**Params**:
+- **date**: Date instance (optional, defaults=`Date.now`)
+
+**Returns**: `this`
+
+### `getSupported()`
+
+Filters `ReleaseLine` items by **isSupported**
+
+**Returns**: `ReleaseLines` instance with only supported release lines.
+
+### `getCurrent()`
+
+Filters `ReleaseLine` items by **isCurrent**
+
+**Returns**: `ReleaseLines` instance with only current release lines.
+
+### `getMaintenance()`
+
+Filters `ReleaseLine` items by **isMaintenance**
+
+**Returns**: `ReleaseLines` instance with only release lines in maintenance mode.
+
+### `getFuture()`
+
+Filters `ReleaseLine` items by **isFuture**
+
+**Returns**: `ReleaseLines` instance with only release lines that have yet to start.
+
+### `getActive()`
+
+Filters `ReleaseLine` items by **isActive**
+
+**Returns**: `ReleaseLines` instance with only release lines that are in LTS, excluding maintenance window.
+
+### `getEOL()`
+
+Filters `ReleaseLine` items by **isEOL**
+
+**Returns**: `ReleaseLines` instance with only release lines that have hit EOL
+
+### `getModern()`
+
+Filters `ReleaseLine` items by **isModern**
+
+**Returns**: `ReleaseLines` instance with only modern release lines.
+
+### `getLTS()`
+
+Filters `ReleaseLine` items by **isLTS**
+
+**Returns**: `ReleaseLines` instance with only release lines that have an LTS active mode in their lifecycle. Note: It does not neccessarily mean it is an active LTS (see `getActive()`).
+
+<a name="Release"></a>
+## `Release` _class_
+
+**Instance properties**:
+- **vulns**: `Array` of [Vulnerability][]
+- **version**: `String` - version number of release
+- **date**: `Date` - date of release
+- **modules**: `Number` - number of modules
+- **npm**: `String` - version
+- **v8**: `String` - version
+- **uv**: `String` - version
+- **zlib**: `String` - version
+- **openssl**: `String` - version
+
+**Instance getters**:
+- **isSafe**: `Boolean` whether a `Release` has any known vulnerabilities.
+- **doc**: `String` url of docs for the specific release
+
+### `download(arch, type)`
+
+If `arch` is omitted returns directory to all download resources for release version.
+
+>Currently `arch` and `type` are not implemented
+
+**options**:
+- **arch**: `String` 
+- **type**: `String` (gz, xz, pkg, msi, zip)
+
+**Returns**: `String` url of download resource
+
+<a name="Releases"></a>
+## `Releases` extends `Array` _class_
+
+An array of `Release` instances. Provides helper methods for updating, filtering and querying release lines.
+
+### `Releases.load(version)` _static_
+
+**Params**:
+- **version**: `String` (example `v6`)
+
+**Returns**: `Releases` instance
+
+### `getSafe()`
+
+Filters `Release` items by **isSafe**
+
+**Returns**: `Releases` instance with only releases that have no known vulnerabilities.
+
+<a name="Vulnerability"></a>
+## `Vulnerability` _class_
+
+**Instance properties**:
+- **id**: `String`
+
+**Instance getters**:
+
+- **cve**
+- **ref**
+- **vulnerable**
+- **patched**
+- **description**
+- **overview**
+- **author**
+- **cvss**
+- **cvss_score**
+- **source**: `String` - url to specific vulnerability in [nodejs/security-wg][] repo.
+- **isValid**: `Boolean`
+
+## Acknowledgements
+
+Thank you [Node.js Release Team][] and all the contributors to the [Node.js project][], without you none of this is possible. Special thanks goes out to [Tierney Cyren][]. His relentless desire to improve accessibility, visibility and communication inspired this project.
+
+## Contributing
+
+To submit a bug report, please create an [issue on GitHub][].
+
+If you'd like to contribute code to this project, please read the
+[CONTRIBUTING.md][] document.
+
+## License & Copyright
+
+**node-release-lines** is Copyright (c) 2018 Nathan White and licensed under the
+MIT license. All rights not explicitly granted in the MIT license are reserved.
+See the included [LICENSE.md][] file for more details.
+
+[Node.js project]: https://nodejs.org/
+[Node.js Release Team]: https://github.com/nodejs/Release#lts-team-members
+[Tierney Cyren]: https://bnb.im/
+[how release lines work]: http://nodesource.com/blog/understanding-how-node-js-release-lines-work/
+[release schedule]: https://raw.githubusercontent.com/nodejs/Release/master/schedule.json
+[nodejs/security-wg]: https://github.com/nodejs/security-wg
+[issue on GitHub]: https://github.com/nw/node-release-lines/issues
+[see terminology]: #terminology
+[Terminology]: #terminology
+[ReleaseLine]: #ReleaseLine
+[ReleaseLines]: #ReleaseLines
+[Release]: #Release
+[Releases]: #Releases
+[Vulnerability]: #Vulnerability
+[CONTRIBUTING.md]: CONTRIBUTING.md
+[LICENSE.md]: LICENSE.md