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Documentation Index

Fetch the complete documentation index at: https://docs.uselayers.com/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

Computed attributes create product values from other product data. You can use them for badges, tiers, tags, filters, sorting, merchandising rules, and storefront API responses. Layers supports two ways to create new computed values:
  • Computed attributes use JavaScript Functions. Choose this when you need custom logic, multiple inputs, templates, previewing, or typed outputs.
  • Derived attributes use the visual Derive builder. Choose this when you want to map values from one source attribute to a new value without writing code.
Existing JSONLogic computed attributes continue to work, but new custom logic should use Functions when possible.

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Functions

Functions let you write JavaScript that receives selected product data and returns a typed result. They are best for calculations such as discount percentage, average margin, SKU coverage, inventory health, or multi-field outputs. Use a Function when you need to:
  • Combine several product fields.
  • Work with variants, prices, tags, metafields, or collection titles.
  • Preview the result on a real product before saving.
  • Return a number, string, boolean, array, object, or multiple generated sub-fields.
See Functions for the full setup guide, supported inputs, output schemas, limitations, and troubleshooting.

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Derive builder

The Derive builder provides a visual interface for deriving an attribute value from another attribute using mapping rules. Use the Derive builder when you want to map values from a source attribute (such as tags or a metafield) to new output values without writing JSONLogic manually. For example, you could derive a “Season” attribute from product tags by mapping tag values like “lightweight” and “breathable” to “Summer”, and “insulated” and “thermal” to “Winter”. How to use:
1

Select a source attribute

Choose any indexed attribute from the Source Attribute dropdown. This is the attribute whose values you want to map from (for example, tags).
2

Define mapping rules

Each rule maps one or more source values to an output value:
  • Match type - Choose how to compare against the source value: Contains, Equals, Starts with, or Ends with.
  • Match values - Select one or more values to match against. Multiple values within a single rule use OR logic (a match on any value triggers the rule).
  • Output value - Enter the derived value to assign when the rule matches.
Click + Add rule to add additional rules. Rules are evaluated top to bottom, and the first matching rule wins.
3

Save the attribute

Once your rules are configured, save the attribute. Layers automatically recalculates all products in the background.
Key behaviors:
  • Case insensitive - All matching is case insensitive by default. “Summer” and “summer” are treated the same.
  • First match wins - Rules are evaluated in order from top to bottom. Once a rule matches, its output value is used and remaining rules are skipped.
  • Default value - When no rule matches, the attribute is excluded from the product’s computed object entirely. It will not appear in API responses for that product.
  • Null and empty exclusion - Computed attributes that evaluate to null or an empty string are automatically excluded from the product data and will not appear in API responses or facet results.
  • Full compatibility - Derived attributes continue to use JSONLogic behind the scenes.
If you need more complex logic than the Derive builder supports, create a computed attribute with a Function.

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Automatic product recalculation

When you create a new computed attribute or update an existing computed attribute’s logic, Layers automatically recalculates all products in your catalog in the background. This applies the computed values across your catalog without manual intervention. During recalculation, any computed attribute that evaluates to null or an empty string is automatically excluded from the product. If a previously stored attribute now evaluates to null or empty, it is removed from the product’s computed data and from any associated facet values.
Recalculation is triggered when you create a computed attribute or modify its logic. Updates to other fields, such as nickname or filterable settings, do not trigger recalculation.

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Data access

Functions use an input query to select the product data they can read. See Function input query. Existing JSONLogic attributes may use legacy data references.

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Platform default computed attributes

The following computed attributes are available by default in the Layers platform:
Description: Ratio between total number of variants and their availability status.Use case: Identify products with partial variant availability.
Description: The number of days since the product became available, based on the imported Published At for the product. If no available date has been imported, the system uses the date the product was created.Use case: Build freshness rules, “new arrivals” groups, and aging product reports.
Description: If the product has a featured image.Use case: Find products that need image cleanup before merchandising.
Description: The age of the most recently created variant.Use case: Highlight products with newly added sizes, colors, or variants.
Description: Whether a product’s variants have different prices.Use case: Identify products where variants do not all share the same price.
For current built-in Function templates, see Computed attribute recipes.

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Recipes

For built-in Function templates covering common computed attributes, see Computed attribute recipes.

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See also