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fieldResolver

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In LIVON, fieldResolver is implemented with fieldOperation.

Use fieldOperation for type-safe field-level resolvers that depend on an entity schema.

import {fieldOperation, object, string} from '@livon/schema';

const User = object({
  name: 'User',
  shape: {
    id: string(),
    name: string(),
  },
});

const GreetingOutput = string();

const userGreetingResolver = fieldOperation({
  dependsOn: User,
  output: GreetingOutput,
  exec: async (entity) => `Hello ${entity.name}`,
});

Key points:

  • dependsOn can be a schema or a shape
  • output is optional but recommended for strict typing
  • api.type is required when fieldOperations are used

dependsOn, input, and output can use any value schema from this section.
API schemas (api) are not valid as field resolver schemas.

Parameters​

  • dependsOn (Schema | Shape, required): source entity schema (or shape shorthand).
  • input (Schema | Shape, optional): resolver input schema.
  • output (Schema, optional): resolver output schema.
  • exec ((dependsOn, ctx) => result | Promise<result> or (dependsOn, input, ctx) => result | Promise<result>, required): resolver function.
  • doc (SchemaDoc, optional): field resolver metadata.

Chain API​

  • fieldOperation does not expose schema chain methods (return type: FieldOperation<...>, not Schema<T>).
  • Use value schemas for dependsOn, input, and output where chain methods are available.