@stryker-mutator/core/src/config/meta-schema-builder.ts

import { commonTokens, tokens } from '@stryker-mutator/api/plugin';
import type { JSONSchema7 } from 'json-schema';
import { Logger } from '@stryker-mutator/api/logging';

import { coreTokens } from '../di/index.js';

export class MetaSchemaBuilder {
  public static inject = tokens(coreTokens.validationSchema, commonTokens.logger);
  constructor(private readonly schema: JSONSchema7, private readonly log: Logger) {}

  public buildMetaSchema(pluginSchemaContributions: Array<Record<string, unknown>>): JSONSchema7 {
    this.log.debug('Contributing %s schemas from plugins to options validation.', pluginSchemaContributions.length);
    return mergedSchema(this.schema, pluginSchemaContributions);
  }
}
function mergedSchema(mainSchema: JSONSchema7, additionalSchemas: JSONSchema7[]): JSONSchema7 {
  const schema = {
    ...mainSchema,
    properties: {
      ...mainSchema.properties,
    },
    definitions: {
      ...mainSchema.definitions,
    },
  };

  Object.assign(schema.properties, ...additionalSchemas.map((s) => s.properties));
  Object.assign(schema.definitions, ...additionalSchemas.map((s) => s.definitions));
  return schema;
}