I have a setInterval setup which internally calls an API. Based on the api response I manage previousState & currentState variables.
I need to make sure that every next setInterval stuff happens when the previous has updated by variables already.
How can I do it?
let previous = null;
let current = null;
const fakeApi = () => {
return new Promise((resolve) => setTimeout(resolve(1), 3000));
};
async function fetchData() {
current = await fakeApi();
callB(previous, current);
previous = current;
}
function getStats(cb) {
setInterval(fetchData, 3000);
}
function callB(prev, curr) {
console.log(prev + " >>> " + curr);
}
getStats(callB);
Instead of setInterval, you could create an sleep function and then call the fetchData after its finished
let previous = null;
let current = null;
const fakeApi = () => {
return new Promise((resolve) => setTimeout(resolve(1), 3000));
};
const sleep = (ms) => new Promise(res => setTimeout(res, ms));
async function fetchData() {
current = await fakeApi();
callB(previous, current);
previous = current;
await sleep(3000);
return fetchData()
}
function callB(prev, curr) {
console.log(prev + " >>> " + curr);
}
getStats(callB);
You could add a while loop to repeatedly call the api function:
let previous = null;
let current = null;
const fakeApi = async () => {
return new Promise(resolve => setTimeout(resolve, 3000));
};
let getStats = async ()=>{
while(true) {
await fakeApi()
callB(previous, current);
previous = current;
await new Promise(resolve => setTimeout(resolve, 3000)); //add delay between updates as required
}
})()
function callB(prev, curr) {
console.log(prev + " >>> " + curr);
}
getStats();