Product Filtering System

Source: Saleor API – ProductFilterInput – Available server-side filter options

When to Use

Use this skill when:

• Modifying product list filtering or sorting
• Adding new filter types
• Working on category, collection, or products pages
• Understanding server-side vs client-side filtering

Instructions

Filter Architecture

Key Files

Server-Side Filtering

Category slugs in URL are resolved to IDs:

// In page.tsx (server component)
import { resolveCategorySlugsToIds, buildFilterVariables } from "@/ui/components/plp/filter-utils";

const categorySlugs = searchParams.categories?.split(",") || [];
const categoryMap = await resolveCategorySlugsToIds(categorySlugs);
const categoryIds = Array.from(categoryMap.values()).map((c) => c.id);

const filter = buildFilterVariables({
	priceRange: searchParams.price,
	categoryIds,
});

// Pass to GraphQL query
const { products } = await executePublicGraphQL(ProductListDocument, {
	variables: { channel, filter },
});

Client-Side Filtering

Colors and sizes are filtered after fetch:

import { filterProducts, extractColorOptions } from "@/ui/components/plp/filter-utils";

// Extract available options
const colorOptions = extractColorOptions(products, selectedColors);

// Apply filters
const filtered = filterProducts(products, {
	colors: selectedColors,
	sizes: selectedSizes,
});

Using the Hook

The useProductFilters hook consolidates all filter logic:

"use client";
import { useProductFilters } from "@/ui/components/plp/useProductFilters";

function ProductsClient({ products, resolvedCategories }) {
	const {
		filteredProducts,
		colorOptions,
		sizeOptions,
		selectedColors,
		handleColorToggle,
		handleSortChange,
		activeFilters,
	} = useProductFilters({
		products,
		resolvedCategories,
		enableCategoryFilter: true,
	});

	return (
		<FilterBar
			colorOptions={colorOptions}
			selectedColors={selectedColors}
			onColorToggle={handleColorToggle}
			// ...
		/>
	);
}

Static Price Ranges

Price ranges are static to avoid UI flicker when filtering:

import { STATIC_PRICE_RANGES_WITH_COUNT } from "@/ui/components/plp/filter-utils";

// Returns: [
//   { label: "Under $50", value: "0-50", count: 0 },
//   { label: "$50 - $100", value: "50-100", count: 0 },
//   ...
// ]

Examples

Adding a New Server-Side Filter

1. Update buildFilterVariables in filter-utils.ts:

export function buildFilterVariables(params: {
	priceRange?: string | null;
	categoryIds?: string[];
	inStock?: boolean; // New filter
}): ProductFilterInput | undefined {
	// ... existing code ...

	if (params.inStock) {
		filter.stockAvailability = "IN_STOCK";
		hasFilter = true;
	}
}

2. Parse from URL in page.tsx and pass to the function.

Anti-patterns

❌ Don’t filter categories client-side – Use server-side with IDs
❌ Don’t generate dynamic price ranges – Use static ranges
❌ Don’t hide selected filters – Always show so users can deselect