Inspect a JavaScript regular expression AST without executing matches.
Your input
Outputs are cleared when the input changes.
Result
Enter your data or use the example, then run the tool.
Worked example
The sample combines a named group, Unicode letter property and lookbehind. Node ranges use UTF-16 offsets.
Method
regjsparser builds the actual AST with named groups, lookbehind, Unicode properties/sets and modifier features enabled. Node type identifiers remain upstream code names.
Limits
Pattern ≤10,000 characters, AST depth ≤60 / 20,000 JSON nodes. Flags are unique dgimsuvy; u and v are mutually exclusive. JavaScript syntax only, not full PCRE. Parsing does not execute regex, prove safe runtime or rule out ReDoS.
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