Infer babel settings from file type

babel-parse-auto.js

const recast = require('recast');
const babylon = require('@babel/parser');

function getParseCallOptions({ parse, ...parseOptions }) {
  return { parse, parseOptions };
}

function getPrintCallOptions({ print, ...printOptions }) {
  return { print, printOptions };
}

class AutoParserBabylon {
  static get supportedFileTypes() {
    return {
      '.js': {},
      '.cjs': {},
      '.mjs': {},
      '.json': { parse: babylon.parseExpression },
      '.ts': { parseOptions: { plugins: ['typescript'] } },
      '.jsx': { parseOptions: { plugins: ['jsx'] } },
      '.tsx': { parseOptions: { plugins: ['jsx', 'typescript'] } },
      '.js.flow': { parseOptions: { plugins: ['flow'] } },
      '.json.flow': { parse: babylon.parseExpression, parseOptions: { plugins: ['flow'] } },
    };
  }

  static mergeOptions(aOptions, bOptions) {
    return {
      parseOptions: {
        ...aOptions.parseOptions,
        ...bOptions.parseOptions,
        plugins: [
          ...(aOptions.parseOptions ? aOptions.parseOptions.plugins || [] : []),
          ...(bOptions.parseOptions ? bOptions.parseOptions.plugins || [] : []),
        ],
      },
      printOptions: {
        ...aOptions.printOptions,
        ...bOptions.printOptions,
      },
    };
  }

  constructor(options = {}) {
    const { mergeOptions } = this.constructor;
    this.options = mergeOptions(options, { parseOptions: { tokens: true } });
  }

  parse(content, options) {
    const { mergeOptions } = this.constructor;
    const { parse = babylon.parse, parseOptions } = mergeOptions(
      this.options,
      getParseCallOptions(options),
    );

    return recast.parse(content, {
      parser: {
        parse: (source) => {
          return parse(source, parseOptions);
        },
      },
    });
  }

  print(ast, options) {
    const { print = recast.print, printOptions } = this.mergeOptions(
      this.options,
      getPrintCallOptions(options),
    );
    return print(ast, printOptions);
  }
}

module.exports = MacromeParserBabylon;