rm unused urlparam

src/lib/utils/url-state.ts

@@ -39,6 +39,30 @@ export function syncSearchParams(url: URL, updates: Record<string, string | null
 	}
 }
 
+/**
+ * The value to mirror, or null when it is the view's default. Defaults belong
+ * in the code, not the query string: a shared link should carry only what the
+ * visitor actually changed, and going back to the default has to clear the
+ * parameter again rather than pin the default in place.
+ */
+export function unlessDefault(value: string | null | undefined, fallback: string): string | null {
+	return value && value !== fallback ? value : null;
+}
+
+/**
+ * Same, for the comma-separated list parameters. Order counts - the models are
+ * plotted, coloured and legended in the order they are listed, so a reordered
+ * line-up is a different view even when it holds the same entries.
+ */
+export function listUnlessDefault(
+	values: string[] | null | undefined,
+	fallback: string[]
+): string | null {
+	if (!values?.length) return null;
+	const joined = values.join(',');
+	return joined === fallback.join(',') ? null : joined;
+}
+
 /** Reads a comma-separated list, dropping empties. */
 export function readList(url: URL, key: string): string[] | null {
 	const raw = url.searchParams.get(key);

src/routes/weather/14-day/[location]/+page.svelte

@@ -7,7 +7,7 @@
 	import { reportPageReady } from '$lib/stores/page-transition.svelte';
 	import { storedEnsembleModel, storedLocation, storedUnits } from '$lib/stores/settings';
 
-	import { syncSearchParams } from '$lib/utils/url-state';
+	import { syncSearchParams, unlessDefault } from '$lib/utils/url-state';
 
 	import { ChartContainer, ChartToolbar } from '$lib/components/charts';
 	import { Label } from '$lib/components/ui/label';
@@ -56,10 +56,12 @@
 		storedLocation.set(data.location);
 	});
 
+	const DEFAULT_MODEL = 'ncep_gefs_seamless';
+
 	let params = $state({
 		...defaultParameters,
 		hourly: ['temperature_2m', 'precipitation', 'wind_speed_10m', 'cloud_cover', 'pressure_msl'],
-		models: ['ncep_gefs_seamless']
+		models: [DEFAULT_MODEL]
 	});
 
 	// units live in a persisted store; mirror them into params so a change
@@ -94,7 +96,7 @@
 	$effect(() => {
 		const model = params.models?.[0];
 		if (!mounted || !model) return;
-		syncSearchParams(get(page).url, { model });
+		syncSearchParams(get(page).url, { model: unlessDefault(model, DEFAULT_MODEL) });
 	});
 
 	// components persist across refetches; entries are null while unmounted
@@ -296,7 +298,7 @@
 {#snippet heroActions()}
 	<div class="lg:absolute lg:right-0 lg:top-0 flex w-full items-center gap-3 sm:w-auto">
 		<ModelSelector
-			selectedModel={params.models?.[0] ?? 'ncep_gefs_seamless'}
+			selectedModel={params.models?.[0] ?? DEFAULT_MODEL}
 			groups={ensembleModelGroups}
 			label={m.model_ensemble()}
 			onModelChange={(model) => {

src/routes/weather/compare/[location]/+page.svelte

@@ -9,7 +9,7 @@
 	import { storedLocation, storedModel, storedUnits } from '$lib/stores/settings';
 
 	import { formatZoned } from '$lib/utils/date';
-	import { readList, syncSearchParams } from '$lib/utils/url-state';
+	import { listUnlessDefault, readList, syncSearchParams } from '$lib/utils/url-state';
 
 	import { ChartContainer, ChartToolbar } from '$lib/components/charts';
 	import { Checkbox } from '$lib/components/ui/checkbox';
@@ -71,10 +71,19 @@
 		storedLocation.set(data.location);
 	});
 
+	const DEFAULT_VARS = ['temperature_2m', 'rain', 'wind_speed_10m'];
+	const DEFAULT_MODELS = [
+		'ecmwf_ifs',
+		'meteofrance_seamless',
+		'ukmo_seamless',
+		'icon_seamless',
+		'gfs_seamless'
+	];
+
 	let params = $state({
 		...defaultParameters,
-		hourly: ['temperature_2m', 'rain', 'wind_speed_10m'],
+		hourly: [...DEFAULT_VARS],
-		models: ['ecmwf_ifs', 'meteofrance_seamless', 'ukmo_seamless', 'icon_seamless', 'gfs_seamless']
+		models: [...DEFAULT_MODELS]
 	});
 
 	// units live in a persisted store; mirror them into params so a change
@@ -125,8 +134,8 @@
 		const vars = params.hourly;
 		if (!mounted) return;
 		syncSearchParams(get(page).url, {
-			models: models?.length ? models.join(',') : null,
+			models: listUnlessDefault(models, DEFAULT_MODELS),
-			vars: vars?.length ? vars.join(',') : null
+			vars: listUnlessDefault(vars, DEFAULT_VARS)
 		});
 	});
 

src/routes/weather/week/[location]/+page.svelte

@@ -18,7 +18,7 @@
 	import { formatZoned } from '$lib/utils/date';
 	import { daySwap, runDayTransition } from '$lib/utils/day-swap';
 	import { buildLocationRoute } from '$lib/utils/location';
-	import { syncSearchParams } from '$lib/utils/url-state';
+	import { syncSearchParams, unlessDefault } from '$lib/utils/url-state';
 
 	import { ChartContainer } from '$lib/components/charts';
 
@@ -269,7 +269,7 @@
 			: false;
 		syncSearchParams(get(page).url, {
 			day: isToday ? null : dayKey,
-			model: model && model !== 'best_match' ? model : null
+			model: unlessDefault(model, 'best_match')
 		});
 	});