arrayFormat: "comma" behavior inconsistency across query-string versions when parsing arrays with commas

[sandeep-exe]

I have a use case where I need to parse and stringify an object containing arrays of strings. These arrays may include strings that contain commas (",") as part of their value. For example:

Example 1:

{
    "prop": ["val1,val2", "val3"]
}

Example 2:

{
    "prop": ["val1,val2"]
}

Code Example:

const stringified = queryString.stringify(a, {
    arrayFormat: "comma",
});

const parsed = queryString.parse(stringified, {
    arrayFormat: "comma",
});

console.log({ parsed, stringified });

The output of the above code varies depending on the version of query-string used.

---

Version 6.12.1:

For Example 1, the output does not split "val1,val2":

{
    "parsed": {
        "prop": ["val1,val2", "val3"]
    },
    "stringified": "prop=val1%2Cval2,val3"
}

For Example 2, the output also does not split "val1,val2":

{
    "parsed": {
        "prop": "val1,val2"
    },
    "stringified": "prop=val1%2Cval2"
}

---

Version 6.14.1:

For Example 1, the output does not split "val1,val2":

{
    "parsed": {
        "prop": ["val1,val2", "val3"]
    },
    "stringified": "prop=val1%2Cval2,val3"
}

For Example 2, the output splits "val1,val2":

{
    "parsed": {
        "prop": ["val1", "val2"]
    },
    "stringified": "prop=val1%2Cval2"
}

---

Version 9.1.1:

For Example 1, the output does not split "val1,val2":

{
    "parsed": {
        "prop": ["val1,val2", "val3"]
    },
    "stringified": "prop=val1%2Cval2,val3"
}

For Example 2, the output splits "val1,val2":

{
    "parsed": {
        "prop": ["val1", "val2"]
    },
    "stringified": "prop=val1%2Cval2"
}

---

Question:

Version 6.12.1 works best for my use case. However, I want to understand:

1. Why do these differences exist between the versions?
2. What should be the expected behavior?
3. Given that I must use arrayFormat: "comma" and cannot switch to another format, how should I handle this issue?

codesandbox: https://codesandbox.io/p/sandbox/query-string-forked-rwvl3y?file=%2Fsrc%2Findex.js