promise vs async await javascript code example
Example 1: js await
const a = async () => {
await b();
c();
};
Example 2: async vs await javascript
fetch('coffee.jpg')
.then(response => {
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
return response.blob();
})
.then(myBlob => {
let objectURL = URL.createObjectURL(myBlob);
let image = document.createElement('img');
image.src = objectURL;
document.body.appendChild(image);
})
.catch(e => {
console.log('There has been a problem with your fetch operation: ' + e.message);
});
Example 3: async vs await javascript
async function myFetch() {
let response = await fetch('coffee.jpg');
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
let myBlob = await response.blob();
let objectURL = URL.createObjectURL(myBlob);
let image = document.createElement('img');
image.src = objectURL;
document.body.appendChild(image);
}
}
myFetch()
.catch(e => {
console.log('There has been a problem with your fetch operation: ' + e.message);
});
Example 4: async vs await javascript
async function myFetch() {
let response = await fetch('coffee.jpg');
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
return await response.blob();
}
myFetch().then((blob) => {
let objectURL = URL.createObjectURL(blob);
let image = document.createElement('img');
image.src = objectURL;
document.body.appendChild(image);
}).catch(e => console.log(e));