This works:
var getArray = function(id) {
return [1, 2];
}
console.log(getArray()[0]); // returns 1This does not work:
var getArray = async function(id) {
return [1, 2];
}
console.log(await getArray()[0]); // syntax errorWhy? How can I change the async/await syntax so it works?
I found the solution, it's very simple. Just wrap the await part with parentheses.
var first = (await getArray())[0];
0 element before awaiting the result.You can use await keyword in another async function to get the desired result via - (await getArray())[0].
If you use async function not inside another async function, it must be used like simple Promise function with calling then.
var getArray = async function(id) {
return [1,2];
}
getArray().then(res => console.log(res[0])).catch(err => {/* ... */});If you want to use await, you need another wrapper async function which will do the logic there and will be just called. Also you can use try/catch within your function
var getArray = async function(id) {
return [1,2];
}
async function printFirst() {
try {
const first = (await getArray())[0];
console.log(first);
} catch(e) {
}
}
printFirst();
await
.catch set.A clearer way to do it is via ES6 destructuring:
const [ topBid ] = await getBids(symbol)
// ^^^ it's the same as:
const topBid = (await getBids(symbol))[0]
In case you need not the first element of an array, there're various destructuring patterns for different scenarios:
awaitoutside of anasync function. Wherever you callgetArray, make thatasyncas well