TypeMismatchedError on Edge

I am running my website with Edge on Window 10. Here is the code the produce the TypeMismatchedError, code: 17

return new Promise((resolve, reject) => {
    return fetch('/api/search/trips', {
      method: 'POST',
      headers: {
        "x-access-token": "example-key",
        'Accept': 'application/json',
        'Content-Type': 'application/json; charset=utf-8'
      },
      body: JSON.stringify(searchData)
    })
    .then(response => response.json())
    .then(json => resolve(json))
    .catch(err => reject(err))
  })

This code throws TypeMismatched exception before any request could be fired. I write it with Webpack.

It works fine in other Chrome, Firefox and Safari. Do you have any idea ?

[Titozzz]

I have the exact same problem. But I guess the answer is does not have to be on this repo but rather around here https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/8546263/

[dgraham]

Try running the fetch call from within Edge’s web console to isolate the code without other dependencies like Webpack.

This handler needs to detect if the request returned a successful response before consuming the JSON response body.

.then(response => response.json())

should be something like this

.then(response => {
  if (response.ok) {
    return response.json()
  } else {
    // HTTP status code not in 200-299 success range
    // Could be 401, 404, 500, etc.
  }
})

Fetch only invokes the catch handler in cases where a Response cannot be created, like network failures, for example. If the HTTP request and response cycle succeeded, the then handler is invoked, even if the HTTP status code is a failure.

Edge has a native implementation of window.fetch and does not use this polyfill code, so I’ll close out this issue.