In a stringified array is it possible to differentiate between quotes that were in a string and those that surrounded the string itself?

Some Context:

• I'm still learning to code atm (started less than a year ago)

• I'm mostly self taught at that since I think my computer science class feels too slow.

• The website I'm learning on is code.org, specifically in the "game lab"

• The site's coding environments only use ES5 because they don't want to update them to ES6 or something like that

• In class we're making function libraries and while not required, I want mine to be "highly usable," for lack of a better term, while also being reasonably short (prefer not to automate things if I can get them done quicker somehow, but that's just personal preference).

So now for where the actual question comes in: in a stringified array, is it possible to differentiate between a quotation mark that was inside a string and a quotation mark that actually denotes a string? Because I noticed something confusing with the output of JSON.parse(JSON.stringify()) on code.org, specifically, if you write something like,

JSON.parse(JSON.stringify(['hi","hi']))  

the output will be ["hi","hi"] which looks just like an array containing two strings (on code.org it doesn't show the \'s), but still contains just one, which is fine unless you're using a regular expression to detect whether or not a match is within a string (if every quotation mark after the match has a "partner"), which is what I'm doing in 4 different functions. One flattens a list (since ES5 doesn't have Array.prototype.flat()), one removes all instances of the arguments from a list, one removes all instances of specified operand types, and one replaces all instances of an argument with the one that follows it.

Now I know the odds of a string containing an odd number of quotation marks (whether single or double) is likely extremely low, but it still bothers me that not having a way to differentiate between quotes formerly within a string and quotes which formerly denoted a string (in an array after it's been stringified) as these functions otherwise function exactly as intended. The regular expression I'm using to determine if there's an even number of quotes left in the stringified array is /(?=[^"]*(?:(?:"[^"]*){2})*$)/ where you put the match before the lookahead assertion and anything you absolutely want to follow before the first [^"]*.

To highlight the actual issue I'm trying to solve, this is my flatten function (since it's the shortest of the 4), and yeah, yeah, I know "eval bad" but it's extremely convenient to use here since it shortens the actual modification into a single line, and I highly doubt anyone's actually going to find a way to abuse it given its implementation ("this" needs to be an array for splice to work, so if I'm not mistaken, there isn't really a way to abuse it, but tell me if I'm wrong, since I probably am).

Array.prototype.flatten = function() {    eval(('this.splice(0,this.length,' + JSON.stringify(this).replace(/[\[\]](?=[^"]*(?:(?:"[^"]*){2})*$)/g, '') + ')').replace(/,(?=((,[^"]*(?:(?:"[^"]*){2})*)*.$))/g, ''));    return this;  };  

This works really well outside of the previously specified conditions, but if I were to call it with something like [1,'"'] it'd find 3 quotation marks after the \[ and wouldn't be able to remove it but would be able to remove the \], thus when eval actually gets to .splice(), it would look like eval('this.splice(0,this.length,[1,"\"")') causing the error Unexpected token ')' to be thrown

Any help on this is appreciated, even if it's just telling me it isn't possible, thanks for reading my ramblings.

TL;DR: in a stringified array is it possible to differentiate between " and \" (string wrapping quotes of strings within a stringified array and quotes within a string within a stringified array) in a regular expression or any other method using only the tools available in ES5 (site I'm learning on doesn't want to update their project environments for whatever reason)

https://stackoverflow.com/questions/66728067/in-a-stringified-array-is-it-possible-to-differentiate-between-quotes-that-were March 21, 2021 at 09:33AM