compute-baseline: Add README and LICENSE files (#934)

Co-authored-by: Philip Jägenstedt <[email protected]>

Author: ddbeck

.gitignore

@@ -1,7 +1,7 @@
 node_modules/
 packages/compute-baseline/dist/
 packages/web-features/index.d.ts
-packages/web-features/LICENSE.txt
+packages/**/LICENSE.txt
 packages/web-features/types.ts
 index.json
 index.js

packages/compute-baseline/README.md

@@ -0,0 +1,113 @@
+# [`compute-baseline`](https://github.com/web-platform-dx/web-features/)
+
+By the [W3C WebDX Community Group](https://www.w3.org/community/webdx/) and contributors.
+
+`compute-baseline` computes preliminary [Baseline statuses](https://github.com/web-platform-dx/web-features/blob/main/docs/baseline.md) from `@mdn/browser-compat-data` feature keys.
+You can use `compute-baseline` to help you find interoperable web platform features, propose new [`web-features`](https://github.com/web-platform-dx/web-features/) features, or compare support between features.
+
+`compute-baseline` also provides utility classes for working with `@mdn/browser-compat-data` generally.
+
+## Limitations
+
+If you need authoritative Baseline statuses, check out the [`web-features`](https://github.com/web-platform-dx/web-features/tree/main/packages/web-features) package instead.
+
+Don't use `compute-baseline` to generate publishable Baseline statuses for arbitrary web platform features.
+The results of `compute-baseline` invocations have _not_ received editorial review.
+Strictly speaking, a Baseline status requires editorial review, so statuses generated by `compute-baseline` are tentative.
+If you need authoritative Baseline statuses, check out the [`web-features`](https://github.com/web-platform-dx/web-features/tree/main/packages/web-features) package instead.
+
+You can use `compute-baseline` to explore possibilities or do error correction.
+For example, you might use `compute-baseline` to hide a Baseline status, when showing a broader feature's status might be misleading.
+
+If you're not sure whether your application fits with the definition of Baseline, please [file an issue](https://github.com/web-platform-dx/web-features/issues/new).
+
+## Prerequisites
+
+To use this package, you'll need:
+
+- Node.js (a supported [current, active LTS, or maintenance LTS release](https://nodejs.org/en/about/previous-releases))
+
+## Install
+
+To install the package, run:
+
+`npm install --save compute-baseline`
+
+If you wish to specify which version of `@mdn/browser-compat-data` (or manage its upgrades explicitly, such as with Dependabot), then install the latest `@mdn/browser-compat-data` too.
+Run:
+
+`npm install --save @mdn/browser-compat-data@latest`
+
+## Usage
+
+### Check support for a group of compat keys
+
+```javascript
+import { computeBaseline } from "compute-baseline";
+
+computeBaseline({
+  compatKeys: [
+    "javascript.builtins.AsyncFunction",
+    "javascript.builtins.AsyncFunction.AsyncFunction",
+    "javascript.operators.async_function",
+    "javascript.operators.await",
+    "javascript.statements.async_function",
+  ],
+});
+```
+
+Returns:
+
+```
+{
+  baseline: 'high',
+  baseline_low_date: '2017-04-05',
+  baseline_high_date: '2019-10-05',
+  discouraged: false,
+  support: Map(7) { … }
+  toJSON: [Function: toJSON]
+}
+```
+
+Use the `toJSON()` method to get a `web-features`-like plain JSON representation of the status.
+
+### Check support for a single support key
+
+Sometimes it can be helpful to know if parent features have less support than the specific feature you're checking (for example, the parent is behind a prefix or flag) when computing a status for a deeply-nested feature.
+This is typically most interesting when checking a single key.
+Use the `withAncestors` option:
+
+```javascript
+import { computeBaseline } from "compute-baseline";
+
+computeBaseline({
+  compatKeys: ["api.Notification.body"],
+  withAncestors: true,
+});
+```
+
+### Bring your own compatibility data
+
+If you don't want to import `@mdn/browser-compat-data` as your data source, you can bring your own schema-compatible compat data.
+
+```javascript
+import data from "some-parsed-json-file";
+import { computeBaseline } from "compute-baseline";
+import { Compat } from "compute-baseline/browser-compat-data";
+
+const compat = new Compat(data);
+
+computeBaseline(
+  {
+    compatKeys: ["css.properties.border-color"],
+  },
+  compat,
+);
+```
+
+<!-- TODO: API reference -->
+
+## Helping out and getting help
+
+`compute-baseline` is part of the W3C WebDX Community Group's web-features project.
+Go to [web-platform-dx/web-features](https://github.com/web-platform-dx/web-features/) for more information on contributing or getting help.

packages/compute-baseline/package.json

@@ -8,13 +8,15 @@
     "./browser-compat-data": "./dist/browser-compat-data/index.js"
   },
   "files": [
-    "dist"
+    "dist",
+    "LICENSE.txt",
+    "README.md"
   ],
   "types": "./dist/index.d.ts",
   "type": "module",
   "scripts": {
     "test": "mocha -r tsx 'src/**/*.test.ts'",
-    "prepare": "tsc"
+    "prepare": "cp ../../LICENSE.txt . && tsc"
   },
   "license": "Apache-2.0",
   "devDependencies": {