Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share … The success function for that promise will have an argument that is a Response object. If you still want to use promises, that’s fine. This means you will get undefined as the return value of apiGetAll. Today I Learned A Hashrocket project Follow on Twitter. Fetch requests are controlled by the connect-src directive of Content Security Policy rather than the directive of the resources it's retrieving.. If the value is a promise, that promise is returned; if the value is a thenable (i.e. The fetch function itself returns a Promise. The Promise.resolve() method returns a Promise object that is resolved with a given value. Response provides multiple promise-based methods to access the body in various formats:. Supplying request options. The fetch function itself returns a Promise. The fetch() method can optionally accept a second parameter, an init object that allows you to control a number of different settings:. We can tidy up the above code using array.reduce: You get a promise of a result. See fetch() for the full options available, and more details. Also, you don’t get a result from a promise. Get the response json with `fetch` and `Promises` The fetch api is intertwined with the Promise api. There's also Promise.reject(val), which creates a promise that rejects with the value you give it (or undefined). has a "then" method), the returned promise will "follow" that thenable, adopting its eventual state; otherwise the returned promise will be fulfilled with the value. So const api will always equal undefined. Second, to get the response body, we need to use an additional method call. If you pass in any other value, e.g., Promise.resolve('Hello'), it creates a promise that fulfills with that value. response.text() – read the response and return as text, response.json() – parse the response as JSON, response.formData() – return the response as FormData object (explained in the next chapter), If you call it with no value, as above, it fulfills with "undefined". The fetch api is intertwined with the Promise api.