Struct JsParser 

pub struct JsParser;

JavaScript parser using PEG grammar.

Parses ES6 JavaScript source code into an ESTree-compliant AST. The parser is built on Pest and follows the ECMAScript 2015 specification.

Examples

use just::parser::JsParser;

let code = "var x = 5 + 3;";
let ast = JsParser::parse_to_ast_from_str(code).unwrap();
assert_eq!(ast.body.len(), 1);

Implementations

impl JsParser

pub fn parse_to_token_tree(script: &str) -> Result<String, String>

Parse JavaScript source into a debug token tree.

Returns a formatted string representation of the parse tree, useful for debugging the parser grammar.

Examples

use just::parser::JsParser;

let code = "var x = 5;";
let tree = JsParser::parse_to_token_tree(code).unwrap();
assert!(tree.contains("script"));

pub fn parse_to_ast(script: Rc<String>) -> Result<ProgramData, JsError<Rule>>

Parse JavaScript source into an AST.

Takes an Rc<String> to allow efficient sharing of the source text across AST nodes for error reporting and formatting.

Examples

use just::parser::JsParser;
use std::rc::Rc;

let code = Rc::new("var x = 5 + 3;".to_string());
let ast = JsParser::parse_to_ast(code).unwrap();
assert_eq!(ast.body.len(), 1);

pub fn parse_to_ast_from_str(script: &str) -> Result<ProgramData, JsError<Rule>>

Parse JavaScript source string into an AST.

Convenience method that wraps the source in an Rc<String>. This is the most commonly used parsing method.

Examples

use just::parser::JsParser;

let code = "function add(a, b) { return a + b; }";
let ast = JsParser::parse_to_ast_from_str(code).unwrap();
assert_eq!(ast.body.len(), 1);

pub fn parse_to_ast_formatted_string( script: &str, ) -> Result<String, JsError<Rule>>

Parse JavaScript and return a formatted AST string.

Useful for debugging and visualizing the AST structure.

Examples

use just::parser::JsParser;

let code = "var x = 5;";
let formatted = JsParser::parse_to_ast_formatted_string(code).unwrap();
assert!(formatted.contains("VariableDeclaration"));

pub fn parse_numeric_string( s: &String, is_error_on_empty: bool, ) -> Result<ExtendedNumberLiteralType, JsError<Rule>>

Parse a numeric literal string.

Supports decimal, hexadecimal (0x), binary (0b), octal (0o), floating point, and scientific notation.

Arguments

• s - The numeric string to parse
• is_error_on_empty - Whether to return an error on empty string

Examples

use just::parser::JsParser;

let hex = "0xFF".to_string();
let result = JsParser::parse_numeric_string(&hex, true).unwrap();