Sveaflet

Sveaflet provides Svelte components for Leaflet mapping components to allow simple construction of declarative maps.

Setup #

  • Svelte
<script>
	import { Map, TileLayer, Marker, Popup } from 'sveaflet';
</script>

<div style="width:100%;height:500px;">
	<Map
		options={{
			center: [51.505, -0.09],
			zoom: 13
		}}
	>
		<TileLayer url={'https://tile.openstreetmap.org/{z}/{x}/{y}.png'} />
		<Marker latLng={[51.505, -0.09]} />
	</Map>
</div>

Here within the Svelte file we create an <Map> component, and wrap the <Map> component with a certain height html element, just like <div>. Then initial the map with options property, the options props is same as Leaflet Class’s options. Nested inside the map we add an <TileLayer> component to provide the OpenStreetMap (opens new window)base layer and its attribution (opens new window), along with an <Marker> component placed at a bound latitude and longitude.

Leaflet elements references #

Each Sveaflet component has its own instance property, through this property, you can call leaflet object’s api to operate relevant objects.

  • Svelte
<script>
	import { Map, TileLayer, Marker, Popup, Circle } from 'sveaflet';
	import { Button } from 'flowbite-svelte';

	let marker;
	let circle;

	function markerOpenPopup() {
		marker && marker.openPopup();
	}

	function circleOpenPopup() {
		circle && circle.openPopup();
	}
</script>

<div class="flex items-center mb-4 gap-4">
	<Button on:click={markerOpenPopup}>Marker openPopup</Button>
	<Button on:click={circleOpenPopup}>Circle openPopup</Button>
</div>
<div style="width:100%;height:500px;">
	<Map
		options={{
			center: [51.505, -0.09],
			zoom: 13
		}}
	>
		<TileLayer url={'https://tile.openstreetmap.org/{z}/{x}/{y}.png'} />
		<Marker latLng={[51.505, -0.09]} bind:instance={marker}>
			<Popup
				options={{
					content: 'Hello Sveaflet.'
				}}
			></Popup>
		</Marker>
		<Circle
			latLng={[51.508, -0.11]}
			options={{
				color: 'red',
				fillColor: '#f03',
				fillOpacity: 0.5,
				radius: 500
			}}
			bind:instance={circle}
		>
			<Popup options={{ content: 'Hello Sveaflet. (Circle)' }} />
		</Circle>
	</Map>
</div>

In this example, we open layer’s popup through marker and circle instance, each component in Sveaflet has its own instance. If you encouter a problem that you can’t solve only by suing Sveaflet components, just use instance. instance is same as object which is Instantiated by Leaflet component class.

Limitations #

When you want to update a component through props, it will update when the props value can be set by leaflet object. For example:

  • Svelte
<script>
	import { Map, TileLayer, Popup } from 'sveaflet';
	import { Radio, Label, Input } from 'flowbite-svelte';

	let content = 'Popup content.';
	let minWidth = 100;
</script>

<div class="flex items-center gap-4 mb-4">
	<Label>Content:</Label>
	<Input type="text" bind:value={content} maxlength={20} />
</div>
<div class="flex items-center gap-4 mb-4">
	<Label>Min Width:</Label>
	<Input type="number" bind:value={minWidth} min={100} max={200} step={10} />
</div>

<div style="width: 100%;height: 500px;">
	<Map options={{ center: [51.505, -0.09], zoom: 13 }}>
		<TileLayer url={'https://tile.openstreetmap.org/{z}/{x}/{y}.png'} />
		<Popup
			latLng={[51.5, -0.09]}
			options={{
				content,
				minWidth
			}}
		/>
	</Map>
</div>

You can update options.content but not options.minWidth, because popup object has setContent() function but doesn’t have setMinWidth() function. Details here.

Quick Start