Sanitize Json String

json_sanitize.js

/**
 * Given you have a JSON string that represents a single object (not array).
 *   SanitizeJsonString will attempt to correct the JSON syntax allowing
 *   it to be parsed. 
 */ 


/**
 * Sanitize user input before attempting to parse the JSON
 *
 * @param str
 * @returns {string}
 * @constructor
 */
var SanitizeJsonString = function(str) {

    if ( ! str ) return "{}";

    return '{' + str
        // wrap numeric values with quotes
        .replace(/\:(\s*\d+)/g, ':"$1"')
        // wrap 'true' values with quotes
        .replace(/\:(\s*true)/g,':"true"')
        // wrap 'false' values with quotes
        .replace(/\:(\s*false)/g,':"false"')
        // replace 'null' values with empty string
        .replace(/\:(\s*null)/g,':""')
        // replace key/value pair separator commas with '@separator@' to avoid confusion
        //  with commas in value strings
        .replace(/\"\s*?\,\s*?\"/g,'"@separator@"')
        // strip curly braces
        .replace(/[{}]/g,'')
        // split on separator
        .split("@separator@")
        // iterate over key value pairs and format them
        .map( function(element) {
                // split the key value pair on the colon character
            var parts = element.split(":"),
                // format the key
                key = SanitizeJsonValue(parts[0]),
                // format the value
                val = SanitizeJsonValue(parts[1]);

            return key + ':' + val;
        })
        // reassemble the string
        .join(",") + '}';
};

/**
 * Sanitize a JSON value
 *
 * @param str
 * @returns {string}
 * @constructor
 */
var SanitizeJsonValue = function(str) {
    if ( ! str ) return '""';

    return '"' + str
        // strip off quotes
        .replace(/^"(.*)"$/, '$1')
        // remove backslashes
        .replace(/\\/g,'')
        // escape slashes
        .replace(/\//g,'\/')
        // escape new lines
        .replace(/\n/g,'\\n')
        // escape form feed
        .replace(/\f/g,'\\f')
        // escape carriage returns
        .replace(/\r/g,'\\r')
        // escape double quote
        .replace(/\"/g,'\\"')
        // escape tabs
        .replace(/\t/g,' ')
        // trim whitespace
        .trim() + '"';
};