Resolvers

Resolvers are hooks that transform context.data, context.result, or context.params.query on a per-property basis. Each property resolver receives the current value, the full data object, the hook context, and resolver metadata. Resolvers run in parallel and errors are collected into a single BadRequest.

Resolver Hooks

Resolver	Description
resolve	Combines data, query, and result resolvers into a single around hook. Data and query resolvers run before next(), while the result resolver runs after. At least one resolver must be provided.
resolveData	Resolves and transforms context.data using a map of resolver functions. Each property in the resolver object receives the current value and can return a transformed value. Runs before next() in the hook pipeline.
resolveQuery	Resolves and transforms context.params.query using a map of resolver functions. Each property in the resolver object receives the current query value and can return a transformed value. Runs before next() in the hook pipeline.
resolveResult	Resolves and transforms context.result using a map of resolver functions. Each property in the resolver object receives the current value and can return a transformed value. Runs after next() in the hook pipeline.

Resolver Helpers

Resolver helpers are factory functions that return resolver property functions for common operations like omitting fields, trimming strings, or setting defaults.

Resolver	Description
defaults	Returns a resolver property that sets a default value when the current value is undefined or null. Accepts a static value or a function that receives the hook context.
fromPredicate	Adapts an existing predicate function (like isProvider, isContext) into a resolver condition. The predicate receives the hook context extracted from the resolver options. Only synchronous predicates are supported.
lowercase	Returns a resolver property that converts string values to lowercase. Non-string values are passed through unchanged.
omit	Returns a resolver property that removes the field by returning undefined. When a condition is provided, the field is only omitted if the condition returns true.
setNow	Returns a resolver property that sets the field to the current timestamp (Date.now()). Always overwrites the existing value.
trim	Returns a resolver property that trims whitespace from string values. Non-string values are passed through unchanged.

Conditions

Conditions control when a resolver helper is applied. They receive the full ResolverPropertyOptions object and return a boolean. When the condition returns false, the helper is skipped and the original value is preserved.

Condition	Description