Modernize for Leaflet v1.x and fix zoom bug

.gitignore

@@ -1 +1,3 @@
-.DS_Store
+.DS_Store
+node_modules/
+package-lock.json

README.md

@@ -1,73 +1,194 @@
 # Leaflet Animated Marker
-[![CDNJS](https://img.shields.io/cdnjs/v/leaflet.AnimatedMarker.svg)](https://cdnjs.com/libraries/leaflet.AnimatedMarker)
 
-This is a Leaflet plugin for animating a marker along a polyline. Check out the [demo](http://openplans.github.com/Leaflet.AnimatedMarker/). Feedback appreciated!
+[![npm version](https://img.shields.io/npm/v/leaflet.animatedmarker.svg)](https://www.npmjs.com/package/leaflet.animatedmarker)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
-## How does it work?
+A Leaflet plugin for animating a marker along a polyline.
 
-It uses CSS3 animations to move the marker from point to point at a specific rate (meter per millisecond). For ancient browsers that don't support CSS3, the polyline is chunked into `distance` segments and moved per `interval` (not so great).
+Check out the [demo](http://openplans.github.com/Leaflet.AnimatedMarker/).
 
-## How can I use it?
+## Requirements
 
-The following code will create an AnimatedMarker that moves along `line`, assuming a `Leaflet.Map` called `map`.
+- Leaflet ^1.0.0
 
-    var line = L.polyline([[40.68510, -73.94136],[40.68576, -73.94149],[40.68649, -73.94165]]),
-        animatedMarker = L.animatedMarker(line.getLatLngs());
+## Installation
 
-    map.addLayer(animatedMarker);
+### npm
 
-## How do I change the rate?
+```bash
+npm install leaflet.animatedmarker
+```
+
+### CDN
+
+```html
+<script src="https://unpkg.com/leaflet.animatedmarker/src/AnimatedMarker.js"></script>
+```
+
+## Usage
+
+### Basic
+
+```javascript
+const line = L.polyline([
+  [40.68510, -73.94136],
+  [40.68576, -73.94149],
+  [40.68649, -73.94165]
+]);
+
+const animatedMarker = L.animatedMarker(line.getLatLngs());
+map.addLayer(animatedMarker);
+```
+
+### With ES Modules
+
+```javascript
+import L from 'leaflet';
+import 'leaflet.animatedmarker';
+
+const animatedMarker = L.animatedMarker(line.getLatLngs());
+```
 
-    var animatedMarker = L.animatedMarker(line.getLatLngs(), {
-      distance: 300,  // meters
-      interval: 2000, // milliseconds
-    });
+### TypeScript
 
+TypeScript definitions are included. The module augments Leaflet's types:
 
-## What if I don't want it to animate right away? Or need to stop it halfway through?
+```typescript
+import L from 'leaflet';
+import 'leaflet.animatedmarker';
 
-    var animatedMarker = L.animatedMarker(line.getLatLngs(), {
-      autoStart: false
-    });
+const marker: L.AnimatedMarker = L.animatedMarker(line.getLatLngs(), {
+  distance: 300,
+  interval: 2000,
+  autoStart: false,
+  onEnd: () => console.log('Animation complete!')
+});
+```
 
-    // Start when you're ready
-    animatedMarker.start();
+## Options
 
-    setTimeout(function() {
-      // Stop the animation
-      animatedMarker.stop();
-    }, 2000);
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `distance` | `number` | `200` | Distance in meters to travel per interval |
+| `interval` | `number` | `1000` | Time in milliseconds to travel the distance |
+| `autoStart` | `boolean` | `true` | Start animating immediately when added to the map |
+| `onEnd` | `function` | `() => {}` | Callback when animation reaches the end |
 
-## Can I give it a custom icon?
+Plus all standard [Leaflet Marker options](https://leafletjs.com/reference.html#marker-option).
 
-Yep! Just like a standard Leaflet.Marker layer.
+## Methods
 
-    var myIcon = L.icon({
-      iconUrl: 'myicon.png'
-    });
+### `start()`
 
-    var animatedMarker = L.animatedMarker(line.getLatLngs(), {
-      icon: myIcon
-    });
+Start the animation from the beginning.
 
-## Can I make the marker explode when it gets to the end of the line?
+```javascript
+animatedMarker.start();
+```
 
-Sure! Just use the `onEnd` callback.
+### `stop()`
 
-    var animatedMarker = L.animatedMarker(line.getLatLngs(), {
-      onEnd: function() {
-        // TODO: blow up this marker
-      }
-    });
-
-## Install via NPM
+Stop the animation at the current position.
 
+```javascript
+animatedMarker.stop();
 ```
-npm install -S leaflet.animatedmarker
+
+### `setLine(latlngs)`
+
+Set a new path for the marker to follow.
+
+```javascript
+animatedMarker.setLine(newPolyline.getLatLngs());
 ```
 
-### Inclusion via npm
+## Examples
 
+### Custom Speed
+
+```javascript
+const animatedMarker = L.animatedMarker(line.getLatLngs(), {
+  distance: 300,  // meters
+  interval: 2000  // milliseconds
+});
 ```
-require('leaflet.animatedmarker/src/AnimatedMarker');
+
+### Manual Control
+
+```javascript
+const animatedMarker = L.animatedMarker(line.getLatLngs(), {
+  autoStart: false
+});
+
+// Start when ready
+animatedMarker.start();
+
+// Stop after 5 seconds
+setTimeout(() => {
+  animatedMarker.stop();
+}, 5000);
 ```
+
+### Custom Icon
+
+```javascript
+const myIcon = L.icon({
+  iconUrl: 'myicon.png'
+});
+
+const animatedMarker = L.animatedMarker(line.getLatLngs(), {
+  icon: myIcon
+});
+```
+
+### Callback on Complete
+
+```javascript
+const animatedMarker = L.animatedMarker(line.getLatLngs(), {
+  onEnd: function() {
+    console.log('Animation finished!');
+    map.removeLayer(this);
+  }
+});
+```
+
+## Development
+
+### Install dependencies
+
+```bash
+npm install
+```
+
+### Run tests
+
+```bash
+npm test
+```
+
+### Run tests in watch mode
+
+```bash
+npm run test:watch
+```
+
+## Changelog
+
+### 1.1.0
+
+- **Fixed:** Marker no longer floats to new position when zooming during animation
+- **Added:** TypeScript type definitions
+- **Added:** UMD module support (AMD, CommonJS, browser globals)
+- **Added:** Vitest test suite
+- **Changed:** Modernized to ES6 syntax
+- **Changed:** Renamed `clickable` option to `interactive` (Leaflet 1.x naming)
+- **Removed:** Legacy fallback for browsers without CSS3 transitions
+- **Removed:** Bower support (deprecated)
+
+### 1.0.0
+
+- Initial release
+
+## License
+
+MIT License - [OpenPlans](https://www.openplans.org/)