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JavaScript Create a Reusable Fetch Function

Rishi B
Rishi B
13,866 Points
Posted by Rishi B
Rishi B
13,866 Points

why 'breed' variable is blank ?

I couldn't get the picture of dog that matches to selected option.

const select = document.getElementById('breeds');
const card = document.querySelector('.card'); 
const form = document.querySelector('form');

// ------------------------------------------
//  FETCH FUNCTIONS
// ------------------------------------------

function fetchData(url){
      return fetch(url).then(res => res.json())
}

fetchData('https://dog.ceo/api/breeds/list')
     .then( data => generateOptions(data.message))

const breed = select.value;

fetchData(`https://dog.ceo/api/breed/${breed}/images/random`)
     .then( data => generateImage(data.message) )

// ------------------------------------------
//  HELPER FUNCTIONS
// ------------------------------------------
function generateOptions(data){
      const options = data.map( item => `
            <option value=${item}>${item}</option>
      `).join('');
      select.innerHTML = options;
}

function generateImage(data){
  card.innerHTML = ` 
          <img src='${data}' >
          <p>click to view images of ${select.value}s</p>
            `;
}

2 Answers

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

As the page first loads, no selection has been made yet so the value is empty. That's why the code in the video only loads a random image to start with.

Later in the lesson, event listeners will be added that will load the breed image after a selection is made by the user.

Rishi B
Rishi B
13,866 Points
Rishi B
Rishi B
13,866 Points

couldn't set the image to match the first option in the Options of 'select' element??

const breed = select.options[0].value;

above line is not working...

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

No, it's also a timing issue. The "fetch" operation is asynchronous, so the assignment happens before any options have been loaded.

To guarantee the sequence, you'd need to make the image fetch part of another "then" chained to the options fetch:

fetchData("https://dog.ceo/api/breeds/list")
  .then(data => generateOptions(data.message))
  .then( _=> fetchData(`https://dog.ceo/api/breed/${select.value}/images/random`)
             .then(data => generateImage(data.message))
  );
Rishi B
Rishi B
13,866 Points
Rishi B
Rishi B
13,866 Points

Thank you so much !!!