Deciphering JSON strings using JavaScript

Question

Deciphering JSON strings using JavaScript

Here is a string that I am trying to parse using Json:

{\"description\": \"PSY - Gangnam Style (\\uac15\\ub0a8\\uc2a4\\ud0c0\\uc77c) \\n\\u25b6 NOW available on iTunes: http:\\\/\\\/Smarturl.it\\\/psygangnam\\n\\u25b6 Official PSY Online Store US \\u0026 International : http:\\\/\\\/psy.shop.bravadousa.com\\\/\\n\\u25b6 About PSY from YG Ent.: http:\\\/\\\/smarturl.it\\\/YGfamilyAboutPSY\\n\\u25b6 PSY's Products on eBay: http:\\\/\\\/stores.ebay.com\\\/ygentertainment\\n\\u25b6 YG-eShop: http:\\\/\\\/www.ygeshop.com\\n \\n===============================\\nPSY CONCERT \\\"HAPPENING\\\"\\n2013.4.13. SAT 6:30PM\\nTHE SEOUL WORLD CUP STADIUM\\nYouTube LIVE@ http:\\\/\\\/www.youtube.com\\\/officialpsy\\nTickets: http:\\\/\\\/smarturl.it\\\/PsyHappeningKor\\nEnglish Booking: http:\\\/\\\/smarturl.it\\\/PsyHappeningEng\\n===============================\\n\\nFor More Information @\\nhttp:\\\/\\\/www.facebook.com\\\/officialpsy\\nhttp:\\\/\\\/twitter.com\\\/psy_oppa\\nhttp:\\\/\\\/twitter.com\\\/ygent_official\\nhttp:\\\/\\\/me2day.net\\\/psyfive\\nhttp:\\\/\\\/www.psypark.com\\nApp Store: http:\\\/\\\/goo.gl\\\/l9TU6\\nGoogle Play: http:\\\/\\\/goo.gl\\\/UiEn1\\n\\n\\u00a9 YG Entertainment Inc. All rights reserved.\"}

My attempt to convert \\" to " with this code:

tmp = tmp.replace(/\\"/gi, '"');

Resulted in the following snippet:

{"description": "PSY - Gangnam Style (\\uac15\\ub0a8\\uc2a4\\ud0c0\\uc77c) \\n\\u25b6 NOW available on iTunes: http:\\\/\\\/Smarturl.it\\\/psygangnam\\n\\u25b6 Official PSY Online Store US \\u0026 International : http:\\\/\\\/psy.shop.bravadousa.com\\\/\\n\\u25b6 About PSY from YG Ent.: http:\\\/\\\/smarturl.it\\\/YGfamilyAboutPSY\\n\\u25b6 PSY's Products on eBay: http:\\\/\\\/stores.ebay.com\\\/ygentertainment\\n\\u25b6 YG-eShop: http:\\\/\\\/www.ygeshop.com\\n \\n===============================\\nPSY CONCERT \\"HAPPENING\\"\\n2013.4.13. SAT 6:30PM\\nTHE SEOUL WORLD CUP STADIUM\\nYouTube LIVE@ http:\\\/\\\/www.youtube.com\\\/officialpsy\\nTickets: http:\\\/\\\/smarturl.it\\\/PsyHappeningKor\\nEnglish Booking: http:\\\/\\\/smarturl.it\\\/PsyHappeningEng\\n===============================
\\nFor More Information @\\nhttp:\\\/\\\/www.facebook.com\\\/officialpsy\\nhttp:\\\/\\\/twitter.com\\\/psy_oppa\\nhttp:\\\/\\\/twitter.com\\\/ygent_official\\nhttp:\\\/\\\/me2day.net\\\/psyfive\\nhttp:\\\/\\\/www.psypark.com\\nApp Store: http:\\\/\\\/goo.gl\\\/l9TU6\\nGoogle Play: http:\\\/\\\/goo.gl\\\/UiEn1\\n\\n\\u00a9 YG Entertainment Inc. All rights reserved."}

However, a snippet still contains

PSY CONCERT \\"HAPPENING\\"\\n2013.4.13. SAT 6:30PM

. Is there a decoding method that can be used to make the string valid for json object parsing?

javascript json

Answer 1

Answer №1

It appears that your string is double-escaped but lacks its outer delimiters.

let str = '{\\"description\\": \\"PSY - Gangnam Style (\\\\uac15\\\\ub0a8\\\\uc2a4\\\\ud0c0\\\\uc77c) … .\\"}';
let jsonStr = JSON.parse('"'+str+'"'),
    obj = JSON.parse(jsonStr);

Answer 2

It appears that your string is double-escaped but lacks its outer delimiters.

let str = '{\\"description\\": \\"PSY - Gangnam Style (\\\\uac15\\\\ub0a8\\\\uc2a4\\\\ud0c0\\\\uc77c) … .\\"}';
let jsonStr = JSON.parse('"'+str+'"'),
    obj = JSON.parse(jsonStr);

Answer 3

Answer №2

One approach, although not ideal, is to evaluate your string before parsing it into JSON:

eval("temp = \"" + temp + "\";");
var tempJSON = JSON.parse(temp);

However, it's important to note that evaluating an unknown string can be risky. It may be safer to explore decoding functions that achieve the same result.

Why does this method work?

Your string appears to resemble a code snippet with escape backslashes used to represent quotes and backslashes. For example, when defining a string as var str = "He said \"ok\"";, the output will be He said "ok". In contrast, if the string contains escape characters within, it would be defined like this:

var str = "He said \\\"ok\\\"";

This would produce a string like:

He said \"ok\"

Within the eval function, everything is interpreted as code. So, executing:

eval("str = \"" + str + "\";");

would effectively run the following line of code:

str = "He said \"ok\"";

resulting in the desired unescaped string:

He said "ok"

Answer 4

One approach, although not ideal, is to evaluate your string before parsing it into JSON:

eval("temp = \"" + temp + "\";");
var tempJSON = JSON.parse(temp);

However, it's important to note that evaluating an unknown string can be risky. It may be safer to explore decoding functions that achieve the same result.

Why does this method work?

Your string appears to resemble a code snippet with escape backslashes used to represent quotes and backslashes. For example, when defining a string as var str = "He said \"ok\"";, the output will be He said "ok". In contrast, if the string contains escape characters within, it would be defined like this:

var str = "He said \\\"ok\\\"";

This would produce a string like:

He said \"ok\"

Within the eval function, everything is interpreted as code. So, executing:

eval("str = \"" + str + "\";");

would effectively run the following line of code:

str = "He said \"ok\"";

resulting in the desired unescaped string:

He said "ok"

Answer 5

Answer №3

While not as sophisticated as the method proposed by basilikum and perhaps not as accurate as the two-step parsing technique recommended by Bergi and Jonathan Lonowsky, an alternative approach could involve utilizing a JavaScript negative lookbehind equivalent. Consider using the following code snippet:

str.replace(/\\+"/gi, function(s){return (s.length % 2) ? s : s.slice(0,-2) + '"';})

It is worth noting that this method offers a more secure solution compared to directly evaluating the string.

Answer 6

While not as sophisticated as the method proposed by basilikum and perhaps not as accurate as the two-step parsing technique recommended by Bergi and Jonathan Lonowsky, an alternative approach could involve utilizing a JavaScript negative lookbehind equivalent. Consider using the following code snippet:

str.replace(/\\+"/gi, function(s){return (s.length % 2) ? s : s.slice(0,-2) + '"';})

It is worth noting that this method offers a more secure solution compared to directly evaluating the string.

Deciphering JSON strings using JavaScript

Answer №1

Answer №2

Answer №3

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