openstapps/packages/json-schema-generator/src/index.ts

import {compileSchema} from './generator/compile-schema.js';
import {generateFiles, Plugin, PluginContext} from '@openstapps/tsup-plugin';
import {JSONSchema7} from 'json-schema';
import {Plugin as EsbuildPlugin} from 'esbuild';
import {createGenerator} from 'ts-json-schema-generator';

export type SchemaConsumer = (this: PluginContext, schema: JSONSchema7) => Record<string, string | Buffer>;

export const jsonSchema: EsbuildPlugin = {
  name: 'json-schema',
  setup(build) {
    const fileRegex = /^schema:/;
    const namespace = 'json-schema-ns';
    const schemas = new Map<string, string>();

    build.onResolve({filter: fileRegex}, ({path, importer}) => {
      const [from, name] = path.replace(fileRegex, '').split('#', 1);

      return {
        path: `${from === 'file' ? importer : from}#${name}`,
        namespace,
      };
    });

    build.onLoad({filter: /.*/, namespace}, ({path}) => {
      if (!schemas.has(path)) {
        const [sourcePath, schemaName] = path.split('#', 1);
        const generator = createGenerator({
          path: sourcePath,
          extraTags: ['elasticsearch'],
          skipTypeCheck: true,
        });
        schemas.set(path, JSON.stringify(generator.createSchema(schemaName)));
      }
      return {
        contents: schemas.get(path),
        loader: 'json',
      };
    });
  },
};

/**
 * TSUp plugin for generating JSONSchema files
 * @param schemaName the name of the generated schema
 * @param schemaConsumers any consumers that can directly use the schema
 */
export function jsonSchemaPlugin(
  schemaName: string,
  ...schemaConsumers: Array<[string, SchemaConsumer]>
): Plugin {
  return {
    name: 'json-schema-generator',
    async buildEnd() {
      let schema: JSONSchema7;
      await generateFiles('JSON-Schema', async function () {
        const [jsonSchema, types] = compileSchema(
          (this.options.entry as string[])[0],
          this.options.tsconfig!,
        );
        schema = jsonSchema;

        return {
          [schemaName]: JSON.stringify(jsonSchema),
          [`${schemaName.replace(/\.json$/, '')}.d.ts`]: types,
        };
      }).call(this);

      for (const [name, consumer] of schemaConsumers) {
        await generateFiles(name, async function () {
          return consumer.call(this, schema);
        }).call(this);
      }
    },
  };
}

export {compileSchema} from './generator/compile-schema.js';