bare-module-lexer

Heuristic lexer for detecting imports and exports in JavaScript modules. It trades off correctness for performance, aiming to reliably support the most common import and export patterns with as little overhead as possible.

Usage

const lex = require('bare-module-lexer')

lex(`
  const foo = require('./foo.js')
  exports.bar = 42
`)

// {
//   imports: [
//     { specifier: './foo.js', type: REQUIRE, names: [], position: [ 15, 24, 32 ] }
//   ],
//   exports: [
//     { name: 'bar', position: [ 37, 45, 48 ] }
//   ]
// }

API

const { imports, exports } = lex(source[, encoding][, options])

imports is an array of objects with the following shape:

{
  specifier: 'string',
  type: number,
  names: ['string'],
  position: [
    number, // Import start
    number, // Specifier start
    number  // Specifier end
  ]
}

exports is an array of objects with the following shape:

{
  name: 'string',
  position: [
    number, // Export start
    number, // Name start
    number  // Name end
  ]
}

Options are reserved.

lex.constants

Constant	Description
REQUIRE	CommonJS require().
IMPORT	ES module import.
DYNAMIC	ES module import() if IMPORT is set.
ADDON	CommonJS require.addon() if REQUIRE is set, or ES module import.meta.addon() if IMPORT is set.
ASSET	CommonJS require.asset() if REQUIRE is set, or ES module import.meta.asset() if IMPORT is set.
RESOLVE	CommonJS require.resolve() or require.addon.resolve() if REQUIRE and optionally ADDON are set, or ES module import.meta.resolve() or import.meta.addon.resolve() if IMPORT and optionally ADDON are set.
REEXPORT	Re-export of a CommonJS require() if REQUIRE is set.

License

Apache-2.0