fetch then catch code example

Example 1: try catch fetch

fetch("/api/foo")
  .then( response => {
    if (!response.ok) { throw response }
    return response.json()  //we only get here if there is no error
  })
  .then( json => {
    this.props.dispatch(doSomethingWithResult(json)) 
  })
  .catch( err => {
    err.text().then( errorMessage => {
      this.props.dispatch(displayTheError(errorMessage))
    })
  })

Example 2: javascript fetch api post

fetch('https://example.com/profile', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
  	'foo': 'bar'
  }),
})
  .then((res) => res.json())
  .then((data) => {
    // Do some stuff ...
  })
  .catch((err) => console.log(err));

Example 3: fetch js

// Example POST method implementation:
async function postData(url = '', data = {}) {
  // Default options are marked with *
  const response = await fetch(url, {
    method: 'POST', // *GET, POST, PUT, DELETE, etc.
    mode: 'cors', // no-cors, *cors, same-origin
    cache: 'no-cache', // *default, no-cache, reload, force-cache, only-if-cached
    credentials: 'same-origin', // include, *same-origin, omit
    headers: {
      'Content-Type': 'application/json'
      // 'Content-Type': 'application/x-www-form-urlencoded',
    },
    redirect: 'follow', // manual, *follow, error
    referrerPolicy: 'no-referrer', // no-referrer, *no-referrer-when-downgrade, origin, origin-when-cross-origin, same-origin, strict-origin, strict-origin-when-cross-origin, unsafe-url
    body: JSON.stringify(data) // body data type must match "Content-Type" header
  });
  return response.json(); // parses JSON response into native JavaScript objects
}

postData('https://example.com/answer', { answer: 42 })
  .then(data => {
    console.log(data); // JSON data parsed by `data.json()` call
  });

Example 4: javascript fetch api get

fetch('http://example.com/movies.json')
  .then(response => response.json())
  .then(data => console.log(data));

Example 5: fetch post js

var myHeaders = new Headers();

var myInit = { method: 'POST',
               headers: myHeaders,
               mode: 'cors',
               cache: 'default' };

fetch('flowers.jpg',myInit)
.then(function(response) {
  return response.blob();
})
.then(function(myBlob) {
  var objectURL = URL.createObjectURL(myBlob);
  myImage.src = objectURL;
});

Example 6: fetch catch

fetch(url).then((response) => {
  if (response.ok) {
    return response.json();
  } else {
    throw new Error('Something went wrong');
  }
})
.then((responseJson) => {
  // Do something with the response
})
.catch((error) => {
  console.log(error)
});