How to fix invalid JSON with RegExp in Javascript?-CodePudding

This is what I've tried

// input
let input = "{id: 1, name: apple, qty: 2, colors: [{id: 1, hex: #f95}], store: {id: 1, name: Apple Store}}"

let result = input.replace((/([\w] )(:)/g), "\"$1\"$2");
// {"id": 1, "name": apple, "qty": 2, "colors": [{"id": 1, "hex": #f95}], "store": {"id": 1, "name": Apple Store}}

And then I just replace it like, replaceAll(': ', ': "'). I think it's not good practice to resolve it, may there is someone who can help me with this problem, thank you so much.

CodePudding user response：

You can convert the stated string that looks almost like an object into an actual JavaScript object with the following assumptions:

keys are composed of alphanumeric and underscores chars
values are treated as numbers if they have the format of a number, e.g. an optional minus sign, followed by digits with optional .
values are treated as a string unless it has the form of a number, or start with [ (array) or { (object)
string values may not contain , or }

const input = "{id: 1, name: apple, qty: 2, colors: [{id: 1, hex: #f95}], store: {id: 1, name: Apple Store}}";
const regex1 = /([,\{] *)(\w ):/g;
const regex2 = /([,\{] *"\w ":)(?! *-?[0-9\.] [,\}])(?! *[\{\[])( *)([^,\}]*)/g;
let json = input
  .replace(regex1, '$1"$2":')
  .replace(regex2, '$1$2"$3"')
let result = JSON.parse(json);
console.log(JSON.stringify(result, null, ' '));

Output:

{
 "id": 1,
 "name": "apple",
 "qty": 2,
 "colors": [
  {
   "id": 1,
   "hex": "#f95"
  }
 ],
 "store": {
  "id": 1,
  "name": "Apple Store"
 }
}

Explanation of regex1:

([,\{] *) -- capture group 1: , or {, followed by optional spaces
(\w ) -- capture group 2: 1 word chars (alphanumeric and underscore)
: -- literal :
replace '$1"$2":' -- capture group 1, followed by capture group 2 enclosed in quotes, followed by colon

Explanation of regex2:

([,\{] *"\w ":) -- capture group 1: , or {, followed by optional spaces, quote, 1 word chars, quote, colon
(?! *-?[0-9\.] [,\}]) -- negative lookahead for optional spaces, a number, followed by , or }
(?! *[\{\[]) -- negative lookahead for optional spaces, followed by { or [
( *) -- capture group 2: optional spaces
([^,\}]*) -- capture group 3: everything that is not a , or }
replace '$1$2"$3"' -- capture group 1, followed by capture group 2, followed by capture group 3 enclosed in quotes

Learn more about regex: https://twiki.org/cgi-bin/view/Codev/TWikiPresentation2018x10x14Regex

CodePudding user response：

Thanks for all answers, I tried this way and its works

    class FixJson {
        constructor() {
            this.run = (json) => {
                const fixDataType = (json) => {
                    for (const key in json) {
                        if (json.hasOwnProperty(key)) {
                            const value = json[key];
                            if (typeof value === 'object') {
                                fixDataType(value);
                            } else if (value === 'true' || value === 'false') {
                                json[key] = value === 'true';
                            } else if (!isNaN(value)) {
                                json[key] = Number(value);
                            }
                        }
                    }
                    return json;
                }
    
                // use the replace function to add double quotes around the property names
                const fixedJson = json.replace(/([a-zA-Z0-9!@#\$%\^\&*\)\( =._-] )/g, '"$1"');
    
                // use the JSON.parse function to parse the fixed JSON string into a JavaScript object
                const obj = JSON.parse(fixedJson);
    
                // fix json data type, and return the result
                return fixDataType(obj)
            }
        }
    }

    const fix = new FixJson()
    let result = fix.run("<your_invalid_json>")