How to promisify correctly JSON.parse method with bluebird

Question

I'm trying to promisify JSON.parse method but unfortunately without any luck. This is my attempt:

Promise.promisify(JSON.parse, JSON)(data).then((result: any) => {...

but I get the following error

Unhandled rejection Error: object

Answer 1

Late to the party, but I can totally understand why you might want a promisified JSON parse method which never throws exceptions. If for nothing else, then to remove boilerplate try/catch-handling from your code. Also, I see no reason why synchronous behavior shouldn't be wrapped in promises. So here:

function promisedParseJSON(json) {
    return new Promise((resolve, reject) => {
        try {
            resolve(JSON.parse(json))
        } catch (e) {
            reject(e)
        }
    })
}

Usage, e.g:

fetch('/my-json-doc-as-string')
  .then(promisedParseJSON)
  .then(carryOn)
  .catch(dealWithIt)