[Javascript] How to solve OOM with the result of toString?

[Yuqi Pan]

I wrote a parser for our database dialect and I want to use it to parse SQL on frontend for formatting purpose. 

But when I run it in browser:

I have tried the solution provided in #1854 which memorizes the result of toString(). It works for a simple SQL but failed with complex one.

Then I took a heap snapshot and found the real reason of OOM:

And my question is should I simplify my parser or is there any improvement for toString() method?

// PredictionContext.js
ArrayPredictionContext.prototype.toString = function() {

Here's my parse tree of following SQL:

SELECT `ename`, `deptno`, `sal`
FROM `emp`
WHERE `deptno`=(SELECT `deptno` FROM `dept` WHERE `loc`='NEW YORK')；

[ML]

Hi,

I met the similar issue, and I fixed that by changing the cache logic. Can you take a look if it works for you? 

PR: https://github.com/antlr/antlr4/pull/2657