How to pass a callback that waits for the setTimeout to finish and return a promise.
Is there any tweak that can be done here to fix this, when a callback is passed from the function which makes the function to resolve after setTimeout
Or call getB before promise.all() and keep the result ready etc
function getA() {
return "A";
}
function getB(callback) {
setTimeout(() => {
callback("B");
}, 10);
}
function getC() {
return Promise.resolve().then(() => "C");
}
function getABC() {
//need to work here only
const cb = (val) => val;
return Promise.all([getA(), getB(cb), getC()]);
}
getABC().then((arr) => console.log(arr));
// expected output [ 'A', 'B', 'C' ]
The expected output is [ 'A', 'B', 'C' ] but receiving [ 'A', undefined, 'C' ]
what changes should I make here?
Update in response to your comment:
function getA () {
return "A";
}
function getB (callback) {
setTimeout(() => {
callback("B");
}, 10);
}
function getC () {
return Promise.resolve().then(() => "C");
}
function getABC () {
const waitForCallback = (invoker) => new Promise(resolve => invoker(resolve));
return Promise.all([getA(), waitForCallback(getB), getC()]);
}
getABC().then(console.log);Original answer:
Return a promise from getB:
function getA () {
return "A";
}
function getB (callback) {
return new Promise(resolve => {
setTimeout(() => {
resolve(callback("B"));
}, 10);
});
}
function getC () {
return Promise.resolve("C");
}
function getABC () {
const cb = (val) => val;
return Promise.all([getA(), getB(cb), getC()]);
}
getABC().then(console.log.bind(console));