await async iife javascript
/* Notes:
1. written like synchronous code
2. compatible with try/catch blocks
3. avoids chaining .then statements
4. async functions always return a promise
5. function pauses on each await expression
6. A non promise value is converted to
Promise.resolve(value) and then resolved
*/
// Syntax
// Function Declaration
async function myFunction(){
await ... // some code goes here
}
// Arrow Declaration
const myFunction2 = async () => {
await ... // some code goes here
}
// OBJECT METHODS
const obj = {
async getName() {
return fetch('https://www.example.com');
}
}
// IN A CLASS
class Obj {
// getters and setter CANNOT be async
async getResource {
return fetch('https://www.example.com');
}
}
fetch('coffee.jpg')
.then(response => {
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
} else {
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);
});
const timeouttt = () => {
return new Promise(resolve => {
setTimeout(() => {
console.log('hey');
resolve('heyyy');
}, 1000);
});
};
const hello5 = async () => {
console.log('hi iqbal');
let y = await (async function () {
let x = await timeouttt();
console.log(x);
console.log('hola');
return 5;
})();
console.log(y);
console.log('vola');
};
hello5()