createFormHelpers.ts

import { InputProps, required } from "ra-core";
import { Schema, SchemaEntityTypes } from "./Schema";

type FormHelpers<S extends Schema> = {
  [EntityType in SchemaEntityTypes<S>]: {
    getInputProps: (attrName: keyof S["entities"][EntityType]) => InputProps;
  };
};

export function createFormHelpers<S extends Schema>(schema: S): FormHelpers<S> {
  type EntityAttributeNames<EntityType extends SchemaEntityTypes<S>> = Extract<
    keyof S["entities"][EntityType],
    string
  >;

  function getInputProps<EntityType extends SchemaEntityTypes<S>>(
    entityType: SchemaEntityTypes<S>,
    attributeName: EntityAttributeNames<EntityType>
  ) {
    const attributeSchema = schema.entities[entityType][attributeName];
    const props: InputProps = {
      source: attributeName,
    };
    if (attributeSchema.required) {
      props.validate = [required()];
    }
    if (attributeSchema.default !== undefined) {
      props.initialValue = attributeSchema.default;
    }
    return props;
  }

  return Object.fromEntries(
    (Object.keys(schema.entities) as SchemaEntityTypes<S>[]).map(
      (entityType) => {
        return [
          entityType,
          {
            getInputProps: <EntityType extends SchemaEntityTypes<S>>(
              attributeName: EntityAttributeNames<EntityType>
            ) => getInputProps(entityType, attributeName),
          },
        ];
      }
    )
  ) as FormHelpers<S>;
}