Why is my fetchData function resulting in an error when I chain a .then() method with a console.log()?

Question

The following function runs just fine...
const fetchData = url => {
  return fetch(url)
    .then(res => res.json())
    .catch(err => console.log("problem: ", err));
}
but when I add a console.log(), it results in "app.js:15 Uncaught (in promise) TypeError: Cannot read property 'message' of undefined
    at fetchData.then.data"...
const fetchData = url => {
  return fetch(url)
    .then(res => console.log(res))
    .then(res => res.json())
    .catch(err => console.log("problem: ", err));
}
I can't figure out why this is happening? the line the error refers to is the very next instance that I use fetchData...
fetchData("https://dog.ceo/api/breeds/list").then(data => generateOptions(data.message))

Seth Kroger · Answer

When you chain then()'s the next then() receives what the previous then() returns. However console.log returns nothing so there is nothing to pass to the next part of the chain.

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Tucker Blackwell

Tucker Blackwell

Why is my fetchData function resulting in an error when I chain a .then() method with a console.log()?

1 Answer

Seth Kroger

Seth Kroger