Provides a front end for Javascript / Typescript AST generation by Babel parser with TyphonJS plugin support. By default all Babel parser plugins are enabled except for flow and there is a handy override mechanism to change relevant defaults without having to provide a full set of options to the parser.

This NPM module can be installed as a dependency in package.json as follows:

"dependencies": {
  "@typhonjs/babel-parser": "^0.2.0"
}

Please see Babel Parser Docs for specific plugin information. By default babel-parser enables all plugins except for flow as it is incompatible with the typescript plugin. Also by default the decorators plugins is enabled and not compatible with decorators-legacy.

The default Babel parser options is as follows:

const s_DEFAULT_BABELPARSER_OPTIONS =
{
   plugins: ['asyncGenerators', 'bigInt', 'classProperties', 'classPrivateProperties', 'classPrivateMethods',
    ['decorators', { decoratorsBeforeExport: false }], 'doExpressions', 'dynamicImport',
     'exportDefaultFrom', 'exportNamespaceFrom',  'functionBind', 'functionSent', 'importMeta',
      'jsx', 'logicalAssignment', 'nullishCoalescingOperator', 'numericSeparator', 'objectRestSpread',
       'optionalCatchBinding', 'optionalChaining', ['pipelineOperator', { proposal: 'minimal' }], 'throwExpressions',
        'typescript']
};

There is a way to provide additional override directives to babel-parser which modifies the default babel parser options above. This only activates when no manual parser options are provided. A third parameter can be passed into parse which will modify the default parameters above. For example Flow is supported by passing in { flow: true } as the override object. This allows flow to be enabled and typescript to be disabled without providing the full babel parser options manually. A few other optional overrides are available:

{
   decoratorsBeforeExport: <boolean>,   // Sets the associated configuration value
   decoratorsLegacy: true,              // Removes the proposal decorators plugin for `decorators-legacy`
   flow: true,                          // Enables flow / disables typescript plugins
   pipelineOperatorProposal: <string>   // Sets the proposal field of pipelineOperator plugin
}

An ES6 example follows:

import BabelParser from '@typhonjs/babel-parser';

// Basic usage to parse text / source code with default options.
const ast = BabelParser.parse(`<some JS or Typescript source code>`);

// Providing custom options
const parserOptions = { plugins: [<any parser options desired to be enabled>] };
const ast = BabelParser.parse(`<some JS or Typescript source code>`, parserOptions);

// Basic usage with default options, but with an override to disable Typescript and enable Flow plugins
const ast = BabelParser.parse(`<some JS w/ Flow typing>`, void 0, { flow: true });

@typhonjs/babel-parser may be loaded as a TyphonJS plugin with typhonjs-plugin-manager and if an eventbus is associated the following event categories are registered:

typhonjs:babel:parser:parse - invokes BabelParser.parse