- The latest ECMAScript version enabled by default (ES2017).
- Comment attachment.
- Support for JSX and Flow.
- Support for experimental language proposals.
Significant diversions are expected to occur in the future such as streaming, EBNF definitions, sweet.js integration, interspacial parsing and more.
allowImportExportEverywhere: By default,
exportdeclarations can only appear at a program's top level. Setting this option to
trueallows them anywhere where a statement is allowed.
allowReturnOutsideFunction: By default, a return statement at the top level raises an error. Set this to
trueto accept such code.
sourceType: Indicate the mode the code should be parsed in. Can be either
sourceFilename: Correlate output AST nodes with their source filename. Useful when generating code and source maps from the ASTs of multiple input files.
plugins: Array containing the plugins that you want to enable.
- Literal token is replaced with StringLiteral, NumericLiteral, BooleanLiteral, NullLiteral, RegExpLiteral
- Property token is replaced with ObjectProperty and ObjectMethod
- MethodDefinition is replaced with ClassMethod
- Program and BlockStatement contain additional
directivesfield with Directive and DirectiveLiteral
- ClassMethod, ObjectProperty, and ObjectMethod value property's properties in FunctionExpression is coerced/brought into the main method node.
AST for JSX code is based on Facebook JSX AST with the addition of one node type: