src/Parser/ESParser.js

import fs from 'fs-extra';
import path from 'path';
import espree from 'espree';
import Plugin from '../Plugin/Plugin.js';

const esmRegex = /(^\s*|[}\);\n]\s*)(import\s*(['"]|(\*\s+as\s+)?[^"'\(\)\n;]+\s*from\s*['"]|\{)|export\s+\*\s+from\s+["']|export\s* (\{|default|function|class|var|const|let|async\s+function))/;

/**
 * ECMAScript Parser class.
 *
 * @example
 * let ast = ESParser.parse('./src/foo.js');
 */
export default class ESParser {
  /**
   * parse ECMAScript source code.
   * @param {string} filePath - source code file path.
   * @returns {AST} AST of source code.
   */
  static parse(filePath) {
    let code = fs.readFileSync(filePath, {encode: 'utf8'}).toString();

    code = Plugin.onHandleCode(code, filePath);

    if (code.charAt(0) === '#') {
      code = code.replace(/^#!/, '//');
    }

    let option = {
      comments: true,
      attachComment: true,
      loc: true,
      ecmaVersion: 6,
      ecmaFeatures:
      {
        jsx: true
      }
    };

    let parser = (code) => {
      option.sourceType = esmRegex.test(code) ? 'module' : 'script';
      return espree.parse(code, option);
    };

    parser = Plugin.onHandleCodeParser(parser, option, filePath, code);

    let ast = parser(code);

    ast = Plugin.onHandleAST(ast, filePath, code);

    return ast;
  }
}