A simple fetch example to get a subreddit json data.

Fetch.js

fetch(`http://www.reddit.com/r/reactjs.json`)
.then(response => {
    if(response.ok) {
        console.log(response);
        return response.json();
    }
    throw new Error('Request failed'); 
})
.then(json => {
    const posts = json.data.children.map(
        obj => obj.data 
    );
    console.log(posts); 
})
.catch(error => { 
    console.error(error);
});