Ошибка json parse error

JSON ( JavaScript Object Notation), is widely used format for asynchronous communication between webpage or mobile application to back-end servers. Due to increasing trend in Single Page Application or Mobile Application, popularity of the JSON is extreme.

Why do we get JSON parse error?

Parsing JSON is a very common task in JavaScript. JSON.parse() is a built-in method in JavaScript which is used to parse a JSON string and convert it into a JavaScript object. If the JSON string is invalid, it will throw a SyntaxError.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json);
console.log(obj.count);
// expected output: 42
console.log(obj.result);
// expected output: true

How to handle JSON parse error?

There are many ways to handle JSON parse error. In this post, I will show you how to handle JSON parse error in JavaScript.

1. Using try-catch block

The most common way to handle JSON parse error is using try-catch block. If the JSON string is valid, it will return a JavaScript object. If the JSON string is invalid, it will throw a SyntaxError.

try {
  const json = '{"result":true, "count":42}';
  const obj = JSON.parse(json);
  console.log(obj.count);
  // expected output: 42
  console.log(obj.result);
  // expected output: true
} catch (e) {
  console.log(e);
  // expected output: SyntaxError: Unexpected token o in JSON at position 1
}

2. Using if-else block

Another way to handle JSON parse error is using if-else block.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json);
if (obj instanceof SyntaxError) {
  console.log(obj);
  // expected output: SyntaxError: Unexpected token o in JSON at position 1
} else {
  console.log(obj.count);
  // expected output: 42
  console.log(obj.result);
  // expected output: true
}

3. Using try-catch block with JSON.parse()

The third way to handle JSON parse error is using try-catch block with JSON.parse().

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json, (key, value) => {
  try {
    return JSON.parse(value);
  } catch (e) {
    return value;
  }
});
console.log(obj.count);
// expected output: 42
console.log(obj.result);
// expected output: true

4. Using try-catch block with JSON.parse() and JSON.stringify()

The fourth way to handle JSON parse error is using try-catch block with JSON.parse() and JSON.stringify(). If the JSON string is valid, it will return a JavaScript object. If the JSON string is invalid, it will return a SyntaxError.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json, (key, value) => {
  try {
    return JSON.parse(value);
  } catch (e) {
    return value;
  }
});
const str = JSON.stringify(obj);
console.log(str);
// expected output: {"result":true,"count":42}

JSON, or JavaScript Object Notation, is a ubiquitous data format used by all sorts of mobile and web apps for asynchronous browser-server communication. JSON is an extremely popular data format, very easy to work with, compatible with every major programming language, and is supported by every major browser. However, just like any programming language, it throws a lot of errors when it decides that today is not going to be your day.

JSON.Parse Syntax Errors

In most web applications, nearly all data transferred from a web server is transmitted in a string format. To convert that string into JSON, we use the JSON.parse() function, and this is the main function that throws errors. Nearly all JSON.parse errors are a subset of the SyntaxError error type. The debugging console throws around 32 different error messages when you mess up your JSON data. And some of them are very tricky to debug; and yes I am talking about you unexpected non-whitespace character after JSON data.

Why the SyntaxError Horror?

SyntaxError is an inherited object of the main error object The main reason behind the error is usually a mistake in the JSON file syntax. You mess up and put a “ instead of a ‘ and you invite to face the SyntaxError JSON.parse: unexpected character.

Just like every programming language, a JSON file has a fixed syntax. Small syntax errors throws errors. For example, in the following code, I forgot to remove a trailing comma

JSON.parse('[a,b, c, d, e, f,]');

Similarly, in this example, I forgot to add the final } character.

JSON.parse('{"LambdaTest": 1,');

How to Catch the Error Before Hand

The problem with debugging JSON errors is that you only get to know about one error at a time. Debuggers throw the first error they find and then stop. It would be up to you to regression find the bugs. Usually, it’s not as difficult as it sounds.

The first step is to make sure that your JSON file is perfect from the get go. Here you can take help from JSON linting tools like cleverly named jsonlint.com

If you don’t have any control over the receiving JSON file, then the next step is to add catch exceptions around your JSON.parse.

function validatingJSON (json) {

  var checkedjson

  try {
    checkedjson = JSON.parse(json)
  } catch (e) {

  }

  return checkedjson }

Also, here are the main errors related to JSON.parse that I very painstakingly collected from a very single source [https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/JSON_bad_parse]:

SyntaxError: JSON.parse: unterminated string literal 
SyntaxError: JSON.parse: bad control character in string literal 
SyntaxError: JSON.parse: bad character in string literal 
SyntaxError: JSON.parse: bad Unicode escape 
SyntaxError: JSON.parse: bad escape character 
SyntaxError: JSON.parse: unterminated string 
SyntaxError: JSON.parse: no number after minus sign 
SyntaxError: JSON.parse: unexpected non-digit 
SyntaxError: JSON.parse: missing digits after decimal point 
SyntaxError: JSON.parse: unterminated fractional number 
SyntaxError: JSON.parse: missing digits after exponent indicator 
SyntaxError: JSON.parse: missing digits after exponent sign 
SyntaxError: JSON.parse: exponent part is missing a number 
SyntaxError: JSON.parse: unexpected end of data 
SyntaxError: JSON.parse: unexpected keyword 
SyntaxError: JSON.parse: unexpected character 
SyntaxError: JSON.parse: end of data while reading object contents 
SyntaxError: JSON.parse: expected property name or '}' 
SyntaxError: JSON.parse: end of data when ',' or ']' was expected 
SyntaxError: JSON.parse: expected ',' or ']' after array element 
SyntaxError: JSON.parse: end of data when property name was expected 
SyntaxError: JSON.parse: expected double-quoted property name 
SyntaxError: JSON.parse: end of data after property name when ':' was expected 
SyntaxError: JSON.parse: expected ':' after property name in object 
SyntaxError: JSON.parse: end of data after property value in object 
SyntaxError: JSON.parse: expected ',' or '}' after property value in object 
SyntaxError: JSON.parse: expected ',' or '}' after property-value pair in object literal 
SyntaxError: JSON.parse: property names must be double-quoted strings 
SyntaxError: JSON.parse: expected property name or '}' 
SyntaxError: JSON.parse: unexpected character 
SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data

If this doesn’t help, then you are in for one long debugging session.

Исключения JavaScript, создаваемые JSON.parse() возникают, когда строку не удалось проанализировать как JSON.

SyntaxError: JSON.parse: unterminated string literal
SyntaxError: JSON.parse: bad control character in string literal
SyntaxError: JSON.parse: bad character in string literal
SyntaxError: JSON.parse: bad Unicode escape
SyntaxError: JSON.parse: bad escape character
SyntaxError: JSON.parse: unterminated string
SyntaxError: JSON.parse: no number after minus sign
SyntaxError: JSON.parse: unexpected non-digit
SyntaxError: JSON.parse: missing digits after decimal point
SyntaxError: JSON.parse: unterminated fractional number
SyntaxError: JSON.parse: missing digits after exponent indicator
SyntaxError: JSON.parse: missing digits after exponent sign
SyntaxError: JSON.parse: exponent part is missing a number
SyntaxError: JSON.parse: unexpected end of data
SyntaxError: JSON.parse: unexpected keyword
SyntaxError: JSON.parse: unexpected character
SyntaxError: JSON.parse: end of data while reading object contents
SyntaxError: JSON.parse: expected property name or 
SyntaxError: JSON.parse: end of data when 
SyntaxError: JSON.parse: expected 
SyntaxError: JSON.parse: end of data when property name was expected
SyntaxError: JSON.parse: expected double-quoted property name
SyntaxError: JSON.parse: end of data after property name when 
SyntaxError: JSON.parse: expected 
SyntaxError: JSON.parse: end of data after property value in object
SyntaxError: JSON.parse: expected 
SyntaxError: JSON.parse: expected 
SyntaxError: JSON.parse: property names must be double-quoted strings
SyntaxError: JSON.parse: expected property name or 
SyntaxError: JSON.parse: unexpected character
SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data

JSON.parse('[1, 2, 3, 4,]');
JSON.parse('{"foo": 1,}');

JSON.parse('[1, 2, 3, 4]');
JSON.parse('{"foo": 1}');

JSON.parse("{'foo': 1}");

JSON.parse('{"foo": 1}');

JSON.parse('{"foo": 01}');



JSON.parse('{"foo": 1.}');

JSON.parse('{"foo": 1}');
JSON.parse('{"foo": 1.0}');

JavaScript

• TypeError: недопустимый операнд «экземпляр» «х»

  Исключение JavaScript «недопустимый операнд экземпляра» возникает, когда оператор правых операндов не используется с объектом конструктора, т.е.

• TypeError: ‘x’ не повторяется

  Исключение JavaScript «не является итерируемым» возникает, когда значение, заданное правой частью for…of, функции аргумента, такой как Promise.all TypedArray.from,

• Синтаксическая ошибка:Некорректный формальный параметр

  Исключение JavaScript «искаженный формальный параметр» возникает, когда список аргументов вызова конструктора Function() каким-то образом недействителен.

• URIError:некорректная последовательность URI

  Исключение JavaScript «неверная последовательность URI» возникает, когда декодирование кодирования не было успешным.

JSON ( JavaScript Object Notation), is widely used format for asynchronous communication between webpage or mobile application to back-end servers. Due to increasing trend in Single Page Application or Mobile Application, popularity of the JSON is extreme.

Why do we get JSON parse error?

Parsing JSON is a very common task in JavaScript. JSON.parse() is a built-in method in JavaScript which is used to parse a JSON string and convert it into a JavaScript object. If the JSON string is invalid, it will throw a SyntaxError.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json);
console.log(obj.count);
// expected output: 42
console.log(obj.result);
// expected output: true

How to handle JSON parse error?

There are many ways to handle JSON parse error. In this post, I will show you how to handle JSON parse error in JavaScript.

1. Using try-catch block

The most common way to handle JSON parse error is using try-catch block. If the JSON string is valid, it will return a JavaScript object. If the JSON string is invalid, it will throw a SyntaxError.

try {
  const json = '{"result":true, "count":42}';
  const obj = JSON.parse(json);
  console.log(obj.count);
  // expected output: 42
  console.log(obj.result);
  // expected output: true
} catch (e) {
  console.log(e);
  // expected output: SyntaxError: Unexpected token o in JSON at position 1
}

2. Using if-else block

Another way to handle JSON parse error is using if-else block.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json);
if (obj instanceof SyntaxError) {
  console.log(obj);
  // expected output: SyntaxError: Unexpected token o in JSON at position 1
} else {
  console.log(obj.count);
  // expected output: 42
  console.log(obj.result);
  // expected output: true
}

3. Using try-catch block with JSON.parse()

The third way to handle JSON parse error is using try-catch block with JSON.parse().

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json, (key, value) => {
  try {
    return JSON.parse(value);
  } catch (e) {
    return value;
  }
});
console.log(obj.count);
// expected output: 42
console.log(obj.result);
// expected output: true

4. Using try-catch block with JSON.parse() and JSON.stringify()

The fourth way to handle JSON parse error is using try-catch block with JSON.parse() and JSON.stringify(). If the JSON string is valid, it will return a JavaScript object. If the JSON string is invalid, it will return a SyntaxError.

const json = '{"result":true, "count":42}';
const obj = JSON.parse(json, (key, value) => {
  try {
    return JSON.parse(value);
  } catch (e) {
    return value;
  }
});
const str = JSON.stringify(obj);
console.log(str);
// expected output: {"result":true,"count":42}

JSON, or JavaScript Object Notation, is a ubiquitous data format used by all sorts of mobile and web apps for asynchronous browser-server communication. JSON is an extremely popular data format, very easy to work with, compatible with every major programming language, and is supported by every major browser. However, just like any programming language, it throws a lot of errors when it decides that today is not going to be your day.

JSON.Parse Syntax Errors

In most web applications, nearly all data transferred from a web server is transmitted in a string format. To convert that string into JSON, we use the JSON.parse() function, and this is the main function that throws errors. Nearly all JSON.parse errors are a subset of the SyntaxError error type. The debugging console throws around 32 different error messages when you mess up your JSON data. And some of them are very tricky to debug; and yes I am talking about you unexpected non-whitespace character after JSON data.

Why the SyntaxError Horror?

SyntaxError is an inherited object of the main error object The main reason behind the error is usually a mistake in the JSON file syntax. You mess up and put a “ instead of a ‘ and you invite to face the SyntaxError JSON.parse: unexpected character.

Just like every programming language, a JSON file has a fixed syntax. Small syntax errors throws errors. For example, in the following code, I forgot to remove a trailing comma

JSON.parse('[a,b, c, d, e, f,]');

Similarly, in this example, I forgot to add the final } character.

JSON.parse('{"LambdaTest": 1,');

How to Catch the Error Before Hand

The problem with debugging JSON errors is that you only get to know about one error at a time. Debuggers throw the first error they find and then stop. It would be up to you to regression find the bugs. Usually, it’s not as difficult as it sounds.

The first step is to make sure that your JSON file is perfect from the get go. Here you can take help from JSON linting tools like cleverly named jsonlint.com

If you don’t have any control over the receiving JSON file, then the next step is to add catch exceptions around your JSON.parse.

function validatingJSON (json) {

  var checkedjson

  try {
    checkedjson = JSON.parse(json)
  } catch (e) {

  }

  return checkedjson }

Also, here are the main errors related to JSON.parse that I very painstakingly collected from a very single source [https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/JSON_bad_parse]:

SyntaxError: JSON.parse: unterminated string literal 
SyntaxError: JSON.parse: bad control character in string literal 
SyntaxError: JSON.parse: bad character in string literal 
SyntaxError: JSON.parse: bad Unicode escape 
SyntaxError: JSON.parse: bad escape character 
SyntaxError: JSON.parse: unterminated string 
SyntaxError: JSON.parse: no number after minus sign 
SyntaxError: JSON.parse: unexpected non-digit 
SyntaxError: JSON.parse: missing digits after decimal point 
SyntaxError: JSON.parse: unterminated fractional number 
SyntaxError: JSON.parse: missing digits after exponent indicator 
SyntaxError: JSON.parse: missing digits after exponent sign 
SyntaxError: JSON.parse: exponent part is missing a number 
SyntaxError: JSON.parse: unexpected end of data 
SyntaxError: JSON.parse: unexpected keyword 
SyntaxError: JSON.parse: unexpected character 
SyntaxError: JSON.parse: end of data while reading object contents 
SyntaxError: JSON.parse: expected property name or '}' 
SyntaxError: JSON.parse: end of data when ',' or ']' was expected 
SyntaxError: JSON.parse: expected ',' or ']' after array element 
SyntaxError: JSON.parse: end of data when property name was expected 
SyntaxError: JSON.parse: expected double-quoted property name 
SyntaxError: JSON.parse: end of data after property name when ':' was expected 
SyntaxError: JSON.parse: expected ':' after property name in object 
SyntaxError: JSON.parse: end of data after property value in object 
SyntaxError: JSON.parse: expected ',' or '}' after property value in object 
SyntaxError: JSON.parse: expected ',' or '}' after property-value pair in object literal 
SyntaxError: JSON.parse: property names must be double-quoted strings 
SyntaxError: JSON.parse: expected property name or '}' 
SyntaxError: JSON.parse: unexpected character 
SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data

If this doesn’t help, then you are in for one long debugging session.

1. 26.08.2015, 06:46

   #1

   

   
   Junior Member
   

   ---

   JSON Parse Error. Func: «pricelist.edit»
   

   Добрый день!

   Проблема с использованием Billmanager последней бета-версии.

   При редактировании тарифных планов или типов продуктов, в момент сохранения и передачи изменений на сервер всплывает ошибка

   JSON Parse Error. Func: «pricelist.edit»

   Методом тыка, выявили что ошибка возникает только при обращении к панели billmgr через url с символом «-» ( в доменном имени ).
   Если заходить по IP-адресу или другому доменному имени без символа «-» то всё сохраняет без ошибок.
   Используем порт https вместо 1500.

   ---

2. 26.08.2015, 12:35

   #2

   

   
   BILLmanager team
   

   ---

   
   

   Добрый день!

   К сожалению на тестовых машинах не воспроизвелось описанное Вами поведение.
   Вероятно проблема воспроизводится при дополнительных параметрах. Не могли бы вы уточнить, какой язык используется, на всех ли тарифах такое поведение, или на каком то одном типе тарифов, либо продуктов. Также может иметь значение непосредственно изменяемый параметр.

   ---

3. 26.08.2015, 18:33

   #3

   

   
   Junior Member
   

   ---

   
   

   Сообщение от t.sidorenko
   

   Добрый день!
   Не могли бы вы уточнить, какой язык используется, на всех ли тарифах такое поведение, или на каком то одном типе тарифов, либо продуктов. Также может иметь значение непосредственно изменяемый параметр.

   Решил проблему, она была как-то связана с добавленным мной для своего типа продукта /usr/local/mgr5/etc/xslt/itemname_exampletype.xsl

   После его удаления и очистки кеша проблема исчезла.

   Не думал что в этом причина , так как же без «-» проблема не вылезала.

   Спасибо!

   ---

4. 30.08.2015, 19:49

   #4

   

   
   Junior Member
   

   ---

   
   

   Уточненные данные по проблеме.
   При прошлом тестировании не совсем гладко были протестированы варианты.
   Похоже, что указанная выше ошибка случается при использовании CloudFlare в качестве фронтенда, напрямую взаимодействующего с ihttpd на 443 порту.

   Сейчас поймал эту ошибку,при попытке снять галочку в таблице «сотрудники»
   после прописывания hostname панели в файл hosts ( в обход cloudflare ) проблема исчезает, после возвращения трафика на clourfire появляется.

   Могли бы вы дать рекомендации по устранению этой проблемы?
   ( кроме вариантов воткнуть промежуточный nginx )

   ---

5. 02.09.2015, 15:43

   #5

   

   
   Junior Member
   

   ---

   ---

6. 02.09.2015, 16:36

   #6

   

   
   ISPsystem team
   

   ---

   
   

   Посмотрите, что там в ответ на это запрос приходит. В разработчике хрома например http://commandlinefanatic.com/cgi-bi…article=art034

   ---

7. 28.05.2016, 18:53

   #7

   

   
   Senior Member
   

   ---

   
   

   Столкнулся с той же проблемой, только через не в ценах, а при сохранении изменений «Редактирование информации о сотруднике»
   Выдает ошибку JSON Parse Error. Func: «employee.edit»
   Chrome console выдает

   jsonParseError app-desktop.min.js?v=5.56.0-2016.05.05_12:52&r=:106

   Основной порт BillManager — 1400
   Захожу через https://dom.exmp.ru
   Если заходить через https://dom.exmp.ru:1400 то проблемы нет

   ---

8. 30.05.2016, 09:40

   #8

   

   
   ISPsystem team
   

   ---

   
   

   Во вкладке Network посмотрите этот запрос, что там прилетает в ответе.

   ---

9. 30.05.2016, 15:48

   #9

   

   
   Senior Member
   

   ---

   
   

   В какой именно вкладке?
   Headers, Preview, Response?

   Последний раз редактировалось Gloome; 30.05.2016 в 18:03.

   ---

10. 31.05.2016, 07:57

    #10

    

    
    ISPsystem team
    

    ---

    ---