objection-swagger/lib/transformers/json-schema.transformer.js

Originally designed as Swagger definition generator for Objection.js models. Since then scope was extended to also cover Swagger-compatible snippets generation from plain JSON Schema entries as well as set of conversions that are useful for model and sche

const _ = require('lodash');

function transformSchema(schema, opts) {
  const processedSchema = _.cloneDeep(schema);
  if (opts.excludeInternalData) {
    delete processedSchema.additionalProperties;
  }
  _processFields(schema, processedSchema);
  return processedSchema;
}

function _processFields(schema, processedSchema) {
  const isFillRequiredList = !processedSchema.required;
  if (!processedSchema.required) {
    processedSchema.required = [];
  }

  _.forOwn(schema.properties, (value, key) => {
    if (value.private) {
      delete processedSchema.properties[key];
    } else {
      //Fill 'required' field field for non-nullable fields
      if (value.type) {
        if (Array.isArray(value.type)) {
          //Swagger 2.0 does not support multiple-value types and neither it does oneOf, so we have to just
          // pick first one
          processedSchema.properties[key].type = value.type[0];
          if (isFillRequiredList && !_propertyIsNullable(value)) {
            processedSchema.required.push(key);
          } else {
            _requiredFieldSanityCheck(
              key,
              processedSchema.required.includes(key),
              _propertyIsNullable(value)
            );
          }
        } else {
          if (isFillRequiredList) {
            processedSchema.required.push(key);
          } else {
            _requiredFieldSanityCheck(
              key,
              processedSchema.required.includes(key),
              _propertyIsNullable(value)
            );
          }
        }
      }

      //process objects additionally
      if (
        processedSchema.properties[key] &&
        processedSchema.properties[key].type === 'object'
      ) {
        _processFields(value, processedSchema.properties[key]);
      }
    }
  });

  //Swagger validation considers empty required attribute to be invalid
  if (processedSchema.required.length === 0) {
    delete processedSchema.required;
  }
}

function _propertyIsNullable(propertyEntry) {
  return (
    Array.isArray(propertyEntry.type) && propertyEntry.type.includes('null')
  );
}

function _requiredFieldSanityCheck(key, isRequired, isNullable) {
  if (isRequired && isNullable) {
    throw new Error(
      `Parameter ${key} is explicitly defined as required and from model it looks like it is nullable. Unable to make decision if field is required.`
    );
  }
}

module.exports = {
  transformSchema,
};