Advertisements I’m stuck with a work-related task where I’m fetching data from the db and then send the data to an external api through post request. Right now I’m succesfully getting the data and processed it but the external api request gets through before the promise is resolved. So I have this service class called… Read More Unable to wait until the promise is resolved
Advertisements When I execute the following code, I thought Node.js will wait till we call the resolve. Till then the myPromise will be in the <pending> state. Then how come node exits before it resolves? The following code exits immediately! const myPromise = new Promise(resolve => { // nothing doing with the resolve }); myPromise… Read More Why Node.js does not wait for promise to resolve before exiting?
Advertisements Problem: last 2 .then are getting called even while i am returning Promise.reject(). 1st .then() is printing undefined and 2nd .then() is also printing the output can someone please explain why? let p4 = new Promise((resolve,reject)=>{ resolve("p4 Resolved"); }); p4.then((val)=>{ console.log(val); return Promise.reject("20 Rejected"); } ) .catch((error)=>{console.log(error)}) .then((val)=>{console.log(val);return 290}) .then((val)=>{console.log("Last then : "+val);}) ;… Read More why .then() is getting called twice in promises {javascript}
Advertisements I have a big problem. I want set some of value in my cookie. but before set in cookie I should encrypt my value and set them in cookie. first my states are undefined and when I navigate to next page those set undefined and made some problems in getting cookies values. how can… Read More How check my state value before call a function?
Advertisements I want to parallel process a number of asynchronous calls in NodeJS. I can continue if a specific number of those calls resolve or all of them are completed(some resolve, some reject). How to to do this? Promise.All() resolves when all of the promises are completed and Promise.Any() resolves when any one of the… Read More Wait for half of the promises to resolve
Advertisements I am executing the code block below. For the jsfiddle line, click here async function sleep(time = 1) { const sleepMilliseconds = time * 1000 return new Promise(resolve => { setTimeout(() => { resolve(`Slept for: ${sleepMilliseconds}ms`) }, sleepMilliseconds) }) } async function main() { let a = [1,2] a.map(async(el)=>{ let i = 3 console.log(el,i)… Read More javascript/nodejs – async code inside while loop which is inside a map array method
Advertisements const promise = new Promise((resolve, reject) => { console.log(“working 1.0”) setTimeout(() => { console.log(“working 2.0”) resolve([90, 70, 55]); }, 7000); }); console.log(“Hi”) promise.then(values => { console.log(values[1]); }); This is the output that I get: working 1.0 Hi working 2.0 70 But why isn’t it: working 1.0 Hi working 1.0 working 2.0 70 My idea… Read More Why does the console.log output during instantiation of a Promise object, but does not output when a ".then()" is called on it?
Advertisements I’m learning Javascript promises and thens, and am confused with this error using Node.js. I would like dostart() to wait until nonblocking sleep is finished, and then return "Resolved" to the main func when it is done. I get this error: dostart().then(value => { ^ TypeError: Cannot read properties of undefined (reading ‘then’) Help… Read More Error with javascript promise and then condition
Advertisements I’m learning node and express and I’m trying to implement a function that retrieves data from a csv file uploaded by the user. The data should be processed first and then outputted to the console, but it instead outputs an empty array before processing it. I followed examples of async/await from tutorials I found… Read More Promises and Async/Await don't seem to do anything in Express/node
Advertisements My co-worker wrote structurally this kind of code: Promise.resolve(2).then(void console.log(‘3’)).then(x => x + 2) Can someone explain why the x argument is not "undefined" in the last then >Solution : Syntax then(onFulfilled) then(onFulfilled, onRejected) Parameters onFulfilled (Optional) A Function asynchronously called if the Promise is fulfilled. This function has one parameter, the fulfillment value.… Read More why does void inside of promise.then not return undefined?