Add improved docs

Author: wooorm

readme.md

@@ -8,34 +8,76 @@
 [![Backers][backers-badge]][collective]
 [![Chat][chat-badge]][chat]
 
-[**unist**][unist] utility to get the positional info of nodes.
+[unist][] utility to get positional info of nodes.
 
-## Install
+## Contents
+
+*   [What is this?](#what-is-this)
+*   [When should I use this?](#when-should-i-use-this)
+*   [Install](#install)
+*   [Use](#use)
+*   [API](#api)
+    *   [`position(node?)`](#positionnode)
+    *   [`pointStart(node?)`](#pointstartnode)
+    *   [`pointEnd(node?)`](#pointendnode)
+*   [Types](#types)
+*   [Compatibility](#compatibility)
+*   [Related](#related)
+*   [Contribute](#contribute)
+*   [License](#license)
+
+## What is this?
+
+This utility helps with accessing positional info on a potentially dirty tree.
+
+## When should I use this?
+
+The positional info is typically consistent and proper in unist trees generated
+by our ecosystem, but, user plugins could mess that up.
+If you’re making a reusable plugin, and accessing the positional info often, you
+might want to guard against that by using this utility.
+
+You might also find the utility [`unist-util-generated`][unist-util-generated]
+useful to check whether a node is considered to be generated (not in the
+original input file).
+
+You might also enjoy
+[`unist-util-stringify-position`][unist-util-stringify-position] when you want
+to display positional info to users.
 
-This package is [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c):
-Node 12+ is needed to use it and it must be `import`ed instead of `require`d.
+## Install
 
-[npm][]:
+This package is [ESM only][esm].
+In Node.js (version 12.20+, 14.14+, 16.0+, 18.0+), install with [npm][]:
 
 ```sh
 npm install unist-util-position
 ```
 
+In Deno with [`esm.sh`][esmsh]:
+
+```js
+import {position, pointStart, pointEnd} from "https://esm.sh/unist-util-position@4"
+```
+
+In browsers with [`esm.sh`][esmsh]:
+
+```html
+<script type="module">
+  import {position, pointStart, pointEnd} from "https://esm.sh/unist-util-position@4?bundle"
+</script>
+```
+
 ## Use
 
 ```js
-import {remark} from 'remark'
+import {fromMarkdown} from 'mdast-util-from-markdown'
 import {position, pointStart, pointEnd} from 'unist-util-position'
 
-const tree = remark().parse('# foo\n\n* bar\n')
+const tree = fromMarkdown('# foo\n\n* bar\n')
 
 console.log(position(tree))
 console.log(pointStart(tree))
-console.log(pointEnd(tree))
-
-console.log(position())
-console.log(pointStart())
-console.log(pointEnd())
 ```
 
 Yields:
@@ -44,33 +86,55 @@ Yields:
 {start: {line: 1, column: 1, offset: 0}, end: {line: 4, column: 1, offset: 13}}
 {line: 1, column: 1, offset: 0}
 {line: 4, column: 1, offset: 13}
-{start: {line: null, column: null, offset: null}, end: {line: null, column: null, offset: null}}
-{line: null, column: null, offset: null}
-{line: null, column: null, offset: null}
 ```
 
 ## API
 
-This package exports the following identifiers: `position`, `pointStart`, and
+This package exports the identifiers `position`, `pointStart`, and
 `pointEnd`.
 There is no default export.
 
 ### `position(node?)`
 
 Get the positional info of `node` ([`Node?`][node]).
-Returns [`Position`][position].
+Returns a proper [`Position`][position].
 
 ### `pointStart(node?)`
 
 ### `pointEnd(node?)`
 
 Get the start or end points in the positional info of `node` ([`Node?`][node]).
-Returns [`Point`][point].
+Returns a proper [`Point`][point].
+
+## Types
+
+This package is fully typed with [TypeScript][].
+It exports no additional types.
+
+## Compatibility
+
+Projects maintained by the unified collective are compatible with all maintained
+versions of Node.js.
+As of now, that is Node.js 12.20+, 14.14+, 16.0+, and 18.0+.
+Our projects sometimes work with older versions, but this is not guaranteed.
+
+## Related
+
+*   [`unist-util-stringify-position`](https://github.com/syntax-tree/unist-util-stringify-position)
+    — serialize a node, position, or point as a human readable location
+*   [`unist-util-position-from-estree`](https://github.com/syntax-tree/unist-util-position-from-estree)
+    — get a position from an estree node
+*   [`unist-util-remove-position`](https://github.com/syntax-tree/unist-util-remove-position)
+    — remove positions from tree
+*   [`unist-util-generated`](https://github.com/syntax-tree/unist-util-generated)
+    — check if a node is generated
+*   [`unist-util-source`](https://github.com/syntax-tree/unist-util-source)
+    — get the source of a node
 
 ## Contribute
 
-See [`contributing.md` in `syntax-tree/.github`][contributing] for ways to get
-started.
+See [`contributing.md`][contributing] in [`syntax-tree/.github`][health] for
+ways to get started.
 See [`support.md`][support] for ways to get help.
 
 This project has a [code of conduct][coc].
@@ -109,17 +173,25 @@ abide by its terms.
 
 [chat]: https://github.com/syntax-tree/unist/discussions
 
+[npm]: https://docs.npmjs.com/cli/install
+
+[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
+
+[esmsh]: https://esm.sh
+
+[typescript]: https://www.typescriptlang.org
+
 [license]: license
 
 [author]: https://wooorm.com
 
-[npm]: https://docs.npmjs.com/cli/install
+[health]: https://github.com/syntax-tree/.github
 
-[contributing]: https://github.com/syntax-tree/.github/blob/HEAD/contributing.md
+[contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md
 
-[support]: https://github.com/syntax-tree/.github/blob/HEAD/support.md
+[support]: https://github.com/syntax-tree/.github/blob/main/support.md
 
-[coc]: https://github.com/syntax-tree/.github/blob/HEAD/code-of-conduct.md
+[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md
 
 [unist]: https://github.com/syntax-tree/unist
 
@@ -128,3 +200,7 @@ abide by its terms.
 [position]: https://github.com/syntax-tree/unist#position
 
 [point]: https://github.com/syntax-tree/unist#point
+
+[unist-util-generated]: https://github.com/syntax-tree/unist-util-generated
+
+[unist-util-stringify-position]: https://github.com/syntax-tree/unist-util-stringify-position