Quick Asynchronous In JS

By promises

• Define a promise:
• establish a method: promise.then(…..after promise is completed)

let lazy = new Promise(resolve=>setTimeout(()=>resolve(‘I am lazy’) ,1000))
lazy.then(result => console.log(result) )

in place of setTimeout there can be a matrix calculation or a network request

without arrow function parent’s ‘this’ context won’t be passed

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By async and await

• function should be marked as an async function
• define your lazy function function as a promise and mark the line as await

async function asyncCall() {
for(i=1; i<=10; i++){
await new Promise(resolve=>setTimeout(()=>resolve(console.log(i)) ,100))
}
}
asyncCall()