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JavaScript Where You’ll Find Promises in the Wild?

Posted by Tony Brackins
Tony Brackins
28,766 Points

Fetch()

I'm looking at this video and doing a fetch function of a URL. It returns a "readable stream" but anyone know how to just return the JSON?

Michael Liendo
Michael Liendo
15,326 Points

Hey Tony, can you share a code snippet?

1 Answer

Chris Shaw
Chris Shaw
26,676 Points

Hi Tony,

The fetch API has a few different helper methods that are bound to the response prototype but we'll simply focus on the json method. As fetch uses promises to pass data around, we can simply use two then callbacks, one to get the parsed JSON and another to do something else with it.

fetch('/path/to/request')
  .then(function(response) {
    // Return the response as a JSON object
    return response.json();
  })
  .then(function(json) {
    console.log(json);
  });

What is happening is we are first waiting for the fetch API to be completed which returns the response stream, then we convert the response value to a JSON object then log that to our console.

Hope that helps.

Tony Brackins
Tony Brackins
28,766 Points

Awesome, that works! Thanks Chris!