regjsgen 
Generate regular expressions from regjsparser’s AST.
Installation
npm i regjsgen
API
regjsgen.generate(ast)
This function accepts an abstract syntax tree representing a regular expression (see regjsparser), and returns the generated regular expression string.
const regjsparser = require('regjsparser');
const regjsgen = require('regjsgen');
// Generate an AST with `regjsparser`.
let ast = regjsparser.parse(regex);
// Modify AST
// …
// Generate `RegExp` string with `regjsgen`.
let regex = regjsgen.generate(ast);
Support
Tested in Node.js 0.10, 0.12, 4, 6, 8, 10, 12 and 14.
Compatible with regjsparser v0.6.4’s AST.