I keep getting “Uncaught SyntaxError: Unexpected token o”

Question

I\'m trying to learn some html/css/javascript, so I\'m writing myself a teaching project.

The idea was to have some vocabulary contained in a json file which would t

Answer 1

const getCircularReplacer = () => {
              const seen = new WeakSet();
              return (key, value) => {
                if (typeof value === "object" && value !== null) {
                  if (seen.has(value)) {
                    return;
                  }
                  seen.add(value);
                }
                return value;
              };
            };
JSON.stringify(tempActivity, getCircularReplacer());

Where tempActivity is fething the data which produces the error "SyntaxError: Unexpected token o in JSON at position 1 - Stack Overflow"

Answer 2

Looks like jQuery takes a guess about the datatype. It does the JSON parsing even though you're not calling getJSON()-- then when you try to call JSON.parse() on an object, you're getting the error.

Further explanation can be found in Aditya Mittal's answer.

Answer 3

Another hints for Unexpected token errors. There are two major differences between javascript objects and json:

1. json data must be always quoted with double quotes.
2. keys must be quoted

Correct JSON

 {
    "english": "bag",
    "kana": "kaban",
    "kanji": "K"
}

Error JSON 1

 {
    'english': 'bag',
    'kana': 'kaban',
    'kanji': 'K'
 }

Error JSON 2

 {
    english: "bag",
    kana: "kaban",
    kanji: "K"
}

Remark

This is not a direct answer for that question. But it's an answer for Unexpected token errors. So it may be help others who stumple upon that question.