\n Babylon is a JavaScript parser used in Babel.\n
\n\n
\n \n \n
\n\n - The latest ECMAScript version enabled by default (ES2017).\n - Comment attachment.\n - Support for JSX and Flow.\n - Support for experimental language proposals (accepting PRs for anything at least [stage-0](https://github.com/tc39/proposals/blob/master/stage-0-proposals.md)).\n\n## Credits\n\nHeavily based on [acorn](https://github.com/marijnh/acorn) and [acorn-jsx](https://github.com/RReverser/acorn-jsx),\nthanks to the awesome work of [@RReverser](https://github.com/RReverser) and [@marijnh](https://github.com/marijnh).\n\nSignificant diversions are expected to occur in the future such as streaming, EBNF definitions, sweet.js integration, interspatial parsing and more.\n\n## API\n\n### `babylon.parse(code, [options])`\n\n### `babylon.parseExpression(code, [options])`\n\n`parse()` parses the provided `code` as an entire ECMAScript program, while\n`parseExpression()` tries to parse a single Expression with performance in\nmind. When in doubt, use `.parse()`.\n\n### Options\n\n- **allowImportExportEverywhere**: By default, `import` and `export`\n declarations can only appear at a program's top level. Setting this\n option to `true` allows them anywhere where a statement is allowed.\n\n- **allowReturnOutsideFunction**: By default, a return statement at\n the top level raises an error. Set this to `true` to accept such\n code.\n\n- **allowSuperOutsideMethod**: TODO\n\n- **sourceType**: Indicate the mode the code should be parsed in. Can be\n either `\"script\"` or `\"module\"`.\n\n- **sourceFilename**: Correlate output AST nodes with their source filename. Useful when generating code and source maps from the ASTs of multiple input files.\n\n- **startLine**: By default, the first line of code parsed is treated as line 1. You can provide a line number to alternatively start with. Useful for integration with other source tools.\n\n- **plugins**: Array containing the plugins that you want to enable.\n\n- **strictMode**: TODO\n\n### Output\n\nBabylon generates AST according to [Babel AST format][].\nIt is based on [ESTree spec][] with the following deviations:\n\n> There is now an `estree` plugin which reverts these deviations\n\n- [Literal][] token is replaced with [StringLiteral][], [NumericLiteral][], [BooleanLiteral][], [NullLiteral][], [RegExpLiteral][]\n- [Property][] token is replaced with [ObjectProperty][] and [ObjectMethod][]\n- [MethodDefinition][] is replaced with [ClassMethod][]\n- [Program][] and [BlockStatement][] contain additional `directives` field with [Directive][] and [DirectiveLiteral][]\n- [ClassMethod][], [ObjectProperty][], and [ObjectMethod][] value property's properties in [FunctionExpression][] is coerced/brought into the main method node.\n\nAST for JSX code is based on [Facebook JSX AST][] with the addition of one node type:\n\n- `JSXText`\n\n[Babel AST format]: https://github.com/babel/babylon/blob/master/ast/spec.md\n[ESTree spec]: https://github.com/estree/estree\n\n[Literal]: https://github.com/estree/estree/blob/master/es5.md#literal\n[Property]: https://github.com/estree/estree/blob/master/es5.md#property\n[MethodDefinition]: https://github.com/estree/estree/blob/master/es2015.md#methoddefinition\n\n[StringLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#stringliteral\n[NumericLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#numericliteral\n[BooleanLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#booleanliteral\n[NullLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#nullliteral\n[RegExpLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#regexpliteral\n[ObjectProperty]: https://github.com/babel/babylon/blob/master/ast/spec.md#objectproperty\n[ObjectMethod]: https://github.com/babel/babylon/blob/master/ast/spec.md#objectmethod\n[ClassMethod]: https://github.com/babel/babylon/blob/master/ast/spec.md#classmethod\n[Program]: https://github.com/babel/babylon/blob/master/ast/spec.md#programs\n[BlockStatement]: https://github.com/babel/babylon/blob/master/ast/spec.md#blockstatement\n[Directive]: https://github.com/babel/babylon/blob/master/ast/spec.md#directive\n[DirectiveLiteral]: https://github.com/babel/babylon/blob/master/ast/spec.md#directiveliteral\n[FunctionExpression]: https://github.com/babel/babylon/blob/master/ast/spec.md#functionexpression\n\n[Facebook JSX AST]: https://github.com/facebook/jsx/blob/master/AST.md\n\n### Semver\n\nBabylon follows semver in most situations. The only thing to note is that some spec-compliancy bug fixes may be released under patch versions.\n\nFor example: We push a fix to early error on something like [#107](https://github.com/babel/babylon/pull/107) - multiple default exports per file. That would be considered a bug fix even though it would cause a build to fail.\n\n### Example\n\n```javascript\nrequire(\"babylon\").parse(\"code\", {\n // parse in strict mode and allow module declarations\n sourceType: \"module\",\n\n plugins: [\n // enable jsx and flow syntax\n \"jsx\",\n \"flow\"\n ]\n});\n```\n\n### Plugins\n\n - `estree`\n - `jsx`\n - `flow`\n - `doExpressions`\n - `objectRestSpread`\n - `decorators` (Based on an outdated version of the Decorators proposal. Will be removed in a future version of `Babylon`)\n - `classProperties`\n - `exportExtensions`\n - `asyncGenerators`\n - `functionBind`\n - `functionSent`\n - `dynamicImport`\n - `templateInvalidEscapes`\n",
"readmeFilename": "README.md",
"repository": {
"type": "git",
"url": "git+https://github.com/babel/babylon.git"
},
"scripts": {
"build": "npm run clean && rollup -c",
"changelog": "git log `git describe --tags --abbrev=0`..HEAD --pretty=format:' * %s (%an)' | grep -v 'Merge pull request'",
"clean": "rimraf lib",
"coverage": "nyc report --reporter=json && codecov -f coverage/coverage-final.json",
"flow": "flow",
"lint": "eslint src bin",
"prepublish": "cross-env BABEL_ENV=production npm run build",
"preversion": "npm run test && npm run changelog",
"test": "npm run lint && npm run flow && npm run build -- -m && npm run test-only",
"test-ci": "nyc npm run test-only",
"test-only": "ava",
"watch": "npm run clean && rollup -c --watch"
},
"version": "6.18.0"
}
![\"babylon\"](\"https://raw.githubusercontent.com/babel/logo/master/babylon.png\"){kind=logo}
\n![\"Travis](\"https://img.shields.io/travis/babel/babylon/master.svg?style=flat&label=travis\")
\n ![\"Codecov](\"https://img.shields.io/codecov/c/github/babel/babylon/master.svg?style=flat\")
\n