Escaping date sometimes results in empty string

[zefir-git]

This is a very weird issue that I was not able to fully debug to find the cause.

Part of my project's code looks like this:

const mysql = require("mysql");
const db = mysql.createConnection(...);

When I run a query with {Date} objects, some of them resulted in a query like (demo)


Running
mysql.escape(new Date()) I get empty string.

I installed mysql and sqlstring on a new plain project and could not reproduce this. mysql.escape(...) seems to work with any other type.

Any ideas what could be the cause for this?

[dougwilson]

Hi @williamd5 sorry you are having this issue. I'm not sure off-hand, but I will try and comb through the code to see under what condition there can be an empty string returned for a Date object. My initial guess from looking at the code is that since the test is val instanceof Date, and Date objects have no enumerable properties, the Date object you are passing in is from a different v8 isolate from the sqlstring module, so gets treated as an empty object.

[dougwilson]

I'm going to mark this as a bug for now, as it should work for Date objects from different isolates, which it doesn't today. Of course, if that is your issue or not, I can't say for sure. If you are able to step through the buggy instance with a debugger, you can check if instanceof Date returns false for the object or not (or I guess edit in a console.log in your node_modules copy of sqlstring).

[zefir-git]

Thank you for the information. I will try to debug as you said and see if I can find anything.

[zefir-git]

In sqlstring lib I added debug to check val instanceof Date and it outputs false. According to this SO answer

you can use the instanceof operator, i.e. But it will return true for invalid dates too, e.g. new Date('random_string') is also instance of Date

date instanceof Date

This will fail if objects are passed across frame boundaries.

A work-around for this is to check the object's class via

Object.prototype.toString.call(date) === '[object Date]'

Here is what I debugged:

The recommended alternative in the SO answer seems to work. I will open a PR on sqlstring with a reference to this issue.

[dougwilson]

Thank you! I am happy to make the fix, but if you want to do it and open a PR, please be sure to add a test case for this condition.

[zefir-git]

If you could make the fix that would be great

[zefir-git]

Any suggestion how to test cross-frame in the tests? I have started a branch on a fork cloudnode-pro/sqlstring@patch/67

[dougwilson]

Hi @williamd5 sorry I was away over the week; I just have a short amount of time today, so wanted to get this fixed for ya. I landed the change + test.