promise

问题 I'm using some Promise() functions to fetch some data and I got stuck with this problem on a project. example1 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo1'); }, 3000); }); example2 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo2'); }, 3000); }); doStuff = () => { const listExample = ['a','b','c']; let s = ""; listExample.forEach((item,index) => { console.log(item); example1().then(() => { console.log("Fisrt"); s =

问题 I'm using some Promise() functions to fetch some data and I got stuck with this problem on a project. example1 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo1'); }, 3000); }); example2 = () => new Promise(function(resolve, reject) { setTimeout(function() { resolve('foo2'); }, 3000); }); doStuff = () => { const listExample = ['a','b','c']; let s = ""; listExample.forEach((item,index) => { console.log(item); example1().then(() => { console.log("Fisrt"); s =

问题 I wrote a promise in javascript to delay an animation until some data is retrieved from my firebase database. The problem is that for some reason the promise isn't working, and the code isn't running asynchronously. Am i not using this promise properly, or is there another issue? var name = document.querySelector('.name') new Promise (function() { firebase.database().ref('users/' + userId ).on('value', function(snap) { console.log('first'); name.innerText = snap.child('name').val(); }); })

问题 So i want to use this effect: useEffect(() => { return db.collection('users').orderBy('lastName').onSnapshot(snap => { const usersArray = [] snap.forEach( async doc => { const user = doc.data() if(user.manager) { await Promise.all([ db.collection('users').doc(user.manager).get(), db.collection('roles').doc(user.profile).get() ]).then(resp => { const manager = resp[0].data() const role = resp[1].data() usersArray.push({ id: doc.id, ...user, manager: `${manager.lastName} ${manager.name} $

问题 So i want to use this effect: useEffect(() => { return db.collection('users').orderBy('lastName').onSnapshot(snap => { const usersArray = [] snap.forEach( async doc => { const user = doc.data() if(user.manager) { await Promise.all([ db.collection('users').doc(user.manager).get(), db.collection('roles').doc(user.profile).get() ]).then(resp => { const manager = resp[0].data() const role = resp[1].data() usersArray.push({ id: doc.id, ...user, manager: `${manager.lastName} ${manager.name} $

问题 I have written a pretty simply script: { waiting: false, async handleWaiting(promise, timeout) { return new Promise((res, rej) => { let loadingStarted = false; const timeoutInstance = setTimeout(() => { loadingStarted = true; this.waiting = true; }, timeout); const onFinished = () => { if (loadingStarted) { this.waiting = false; } clearTimeout(timeoutInstance); } promise .then((result) => { onFinished(); res(result); }) .catch((ex) => { onFinished(); rej(ex); }); }); }, async searchForTerm

问题 I have a function which accepts a string and a path value and checks whether the path at the result returns a 1 or a -1. I fire the function with multiple requests and everything seems to be successful except for one. For example, if I call the function with 10 different URL's continously (one by one, not in an array), the promise is resolved for 9 but not for the 10th one. This is my code: enum Status { Queued = 0, Started = 1, Finished = 2, Failed = -1, } let dataFetchingTimer: number;

问题 I have a function which accepts a string and a path value and checks whether the path at the result returns a 1 or a -1. I fire the function with multiple requests and everything seems to be successful except for one. For example, if I call the function with 10 different URL's continously (one by one, not in an array), the promise is resolved for 9 but not for the 10th one. This is my code: enum Status { Queued = 0, Started = 1, Finished = 2, Failed = -1, } let dataFetchingTimer: number;

问题 This question already has answers here : How to return value from an asynchronous callback function? [duplicate] (3 answers) Closed 1 year ago . A really simply question. I've boiled it down to the simplest version that illustrates my problem. Why does this vanilla JS return a promise, and how can I get it to return "Hello"? let result = test() .then(function(result) { return result; }); alert(result); function test(serialized) { return new Promise(function(resolve, reject) { resolve("Hello")

问题 This question already has answers here : How to return value from an asynchronous callback function? [duplicate] (3 answers) Closed 1 year ago . A really simply question. I've boiled it down to the simplest version that illustrates my problem. Why does this vanilla JS return a promise, and how can I get it to return "Hello"? let result = test() .then(function(result) { return result; }); alert(result); function test(serialized) { return new Promise(function(resolve, reject) { resolve("Hello")