Parsing a user-input value

Question

I would like to allow a user to enter some input, and the program to parse that as a js type, if it can. For example, in what the user types into the text input is:

• Hello -> "Hello" (string)
• 2.13 -> 2.13 (number)
• true -> true (bool)

Would the following accomplish this in a very basic fashion, ignoring nested objects and such?

function parseValueFromText(text) {
    try {
        return JSON.parse(text);
    } catch(e) {
        if (e instanceof SyntaxError) {
            return text;
        } else {
            throw e;
        }
    }
}
let a=parseValueFromText('hello'),
    b=parseValueFromText(123);
console.log(a, typeof a);
console.log(b, typeof b);

Answer 1

Your implementation is pretty close, but if JSON.parse results in a string then you likely want the original string, not the result of the parse.

Also, I think that any exception should result in the original string.

function parseValueFromText(text) {
  try {
    const result = JSON.parse(text);
    if (typeof result !== 'string') return result;
  } catch {}
  return text;
}