CODEWITHSUNDEEP
javascriptjson
erotavlas
erotavlas

Reputation: 4493

JSON stringify unable to escape single quote using replacer function

I'm trying to replace single quotes in my json string values with \' however it is not working only when I try to use the replacer function. 

var myObj = {
test: "'p'"
}

 var replacer = function (key, value) {
                if (typeof value === 'string')
                    return value.replace(/'/g, "\\'");
                else return value;
            };

  var JSONstring = JSON.stringify(myObj, replacer, ' ');

  alert(JSONstring);

https://jsfiddle.net/4fsqozek/1/

However if I do just a simple replace after the string is created like this without using the replacer function

 var JSONstring = JSON.stringify(myObj).replace(/'/g, "\\'");

The regex I used works fine.

EDIT - clarification - using replacer function the output value contains double backslash like this \\'p\\' , which is not what I'm expecting

Can anyone explain this?

Upvotes: 0

Views: 3887

Answers (2)

Jerod Hodgkin
Jerod Hodgkin

Reputation: 26

The value is passed to the replacer before it is stringified. The replacer's escapes are stripped out when the value gets stringified.

This is why calling replace() after the json has been stringified works.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

Upvotes: 0

Paolo
Paolo

Reputation: 15847

JSON.stringify encodes backslashes

see How do I retain backslashes in strings when using JSON.stringify?

As you attempt to insert a backslash in a string that will be JSON encoded the single \ will become \\

However as you will decode the JSON double backslashes \\ then will be decoded into single \ (and I think you'll end up with the desired result).

If you keep your exact code and then at the end you replace the alert(...) with 

alert( JSON.parse( JSONstring ).test );

you get

\'p\'

Upvotes: 2

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