Generate RegExpr from parsed stringified Acorn AST would get [object object]

[snowmantw]

I've found that if I get a parsed AST from Acorn (supports SpiderMonkey Parser API format), and then JSON.stringify it to get serialized version, the one would not be handled correctly even after JSON.parse it.

Example: (Without serialization and de-serialization)

  var source = 'var foo = function () {\n    var a = b.replace(/(\\/)/, \'/bar\');\n};'  // read from file
  var output = escodegen.generate(acorn.parse(source))
  output  //  'var foo = function () {\n    var a = b.replace(/(\\/)/, \'/bar\');\n};'      // the same

As the same with the original source. In contrast:

  var source = 'var foo = function () {\n    var a = b.replace(/(\\/)/, \'/bar\');\n};'
  var output = escodegen.generate(JSON.parse(JSON.stringify(acorn.parse(source))))
  output // 'var foo = function () {\n    var a = b.replace([object Object], \'/bar\');\n};'   // error...

Unfortunately, I only know the shallow reason why the error happens is because generateRegExp expects to accept a reg which would be used as reg.toString to print the regexpr in string, but if it receive a object (although the object is exactly a "regexp" node as {pattern, flags}), it would only print '[object object]'. It looks like the not serialized AST would have a real RegExp with the correct toString method, while serialized one would get rid of it. However, since I have no idea of how the escodegen handle it deeply, maybe this is not the root cause.

[snowmantw]

And my Acorn version is"1.0.3", and escodegen is "1.6.1".

[kxcode]

meet same issue when using JSON and esprima

escodegen.generate(JSON.parse(JSON.stringify(esprima.parse(code))));

will get [object Object] from regex

[kxcode]

any solution now?