Pass promise to function. Question: how do I pass this data in the render function.

Pass promise to function When trying to write a wrapper class for asynchronous DynamoDB calling, I failed with the attempt to wrap all the return statements with a function call as: function Now in your executor function when the promise resolves you call the positionally first function and pass it one value. Is there a way to make it work? If not, any suggestions for work around would be greatly appreciated. I'm trying to pass users last message into the ListItem subtitle prop but I can't seem to find a way to return the value from the promise/then call. UPDATE: As Hobblin said in his comments to the question, now you can pass arguments to the function inside setTimeout using Function. then onto a Promise to make the Promise resolve to the result of the . Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company I have a promise object needs to be parsed to another component, how to achieve this so that when the promise in component-one is resolved, the promise object parsed to component-two can also be re What do you mean by "results in them being called immediately, instead of later when the Promise. I am the author of pg-promise;). I've seen similar questions about passing arguments into . EDIT Fiddle which implements the accepted answer, for the curious. Viewed 2k times I've gone through a few questions similar to this but haven't been able to find one for this specific bit I'm having trouble understanding. js functions in a Promise so as to remove all synchronous code from my Node app, but is this best practice? Pass variables between Promises and functions. For a Node library, I want to be able to pass a log function to a function that returns a Promise. myFunction is not a function. Share. you just need to do some reorganization. When the Promise’s should be Wrap your Promise inside a function or it will start to do its job right away. proxy(function, context, value) is particularly helpful in this case since it:. js needs to wait for the API function until it can be executed. You're not passing r to the functions. An arrow function expression (also known as fat arrow function) has a shorter syntax compared to function expressions and lexically binds the this value (does not bind its own this, arguments, super, or new. Plus, you can pass parameters to the function: return new Promise(function (resolve, reject) { /* stuff using username, password */ if (/* everything turned out fine */) { resolve("Stuff worked!"); } else { If you're making an API call and the API call is successful, then you call the resolve function by passing the result of the API as an argument to it. all, Promise. 1 Assign resolved promise to variable. feed and pass it further as an argument in a completely different function in a different js file which accepts argument of type String ( assumption: vm. 4. var getNameById = function (id) { return Although the async and await keywords are now part of standard JavaScript, under the hood they ultimately use Promises. log). catch() handlers (like you originally had) to the device_get_env(env) calls to see which ones are succeeding/failing. Obviously if I do something like somedataMap. I would like to pass a function (or functions) via a postMessage() to a web worker, because I can't refer to regular files. All those other answers you reference tell you that too. success in there but I specifically want to use toastify promise and want to see how I can pass data in promise. Sometimes you write similar helper functions yourself, e. defer(); setTimeout(funct jQuery's $. Promise. then() is the parameter at subsequent . then() method and . So don't expect to have it execute again. all() at all inside the loop. The receiver of the promise determines, based on program state, what to call next by passing that to promise's then. If you say then(f()), what you're saying is "pass the result of invoking f (which is 'hello') to then'. then(function(res) { Also, you should probably use arrow functions instead, which makes it easier to access data outside of the function scope (as it shares this with its original scope):. Specifically I don't know how to type the addTask property in my interface:. then() method is called - fulfills. Or, you can promisify your . I've just included the alert as a simple way of determining whether the value has been passed. Modified 3 years, 1 month ago. Here is how it All three should trigger the function, but the order differs between the approaches. then(). all to pass some additional variables to the next . then(values => functionC(values[0], values[1])); @IgorAtsberger Yes if you pass some parameters to async/normal function you need to create empty lambda function which will pass those parameters. Just make your own function that accepts the Promises don't run anything, they just observe things that are running. For instance, we write To pass parameters to a promise function in javascript, create a parameter function and use promise in a function like the below example. then – Jaromanda X. The function to be passed in is the database transaction txn function below: db. js, sync), but it seems that it does not fit with my code. It returns a new function that expects the next argument inline. – Therefore, you can easily write a function hook by using the apply() method. Say you have: function f() { return 'hello'; } then() takes a function as its parameter. res. Pass value function. Unlike regular query formatting with pg-promise, where you specify your formatting template through the formatting variables, you skip that when using methods func and proc, and so they are implied from the type of values. Ideally, it's maybe possible for the compiler to determine that farmerToUpdate will actually never be null in the nested function, but it is more complex and the compiler just doesn't support that I think. I need to pass some arguments to a promise but promises only take two parameters (resolve and reject). then xhr(url[i]). – ahnbizcad. This way the program will wait on the await line until the Promise is resolved and then continue. It then calls the promise method (or another promise method, or really any . catch() handler to see if there are any errors. Here we’ll explore what Promises are, why they’re When you create a Promise, you pass in a callback function as an argument. It would be a function that extracts promises from properties on an object, puts them in an array, calls Promise. Transform your function to something like this. then() functions, but none about the promises themselves. prototype. f gets invoked right away. If you want to end up with an array if objects that have id and balance in them, you can do something like this. I'm Put the fetch function in a useEffect in the parent component and make arr a state variable. That's not how it works - you must pass callback functions, everything else will be ignored But the nested function has it's own scope, and in it the farmerToUpdate's type is still nullable. This function cannot return true or false, as it doesn't know if the call was successfull or not. feed contains data of type String). My question is do I have to ´addEventListener´ in the promise std::async (and other functions that do perfect forwarding) look at the type of the argument that you pass to figure out what to do. So saying then(f) says "invoke f after the promise resolves. all([functionA, functionB]). then(doSomething("2nd Call")) instead of registering a callback function which will be invoked at some later time, doSomething() is called immediately. log('chargeCreditCard() function called!'); callback(); } If you want to call this function do something like I tried to encapsulate this function into separate promises, also tried with npm packages (synchronous. You are currently passing arbitrary strings, which is useless You can use console. The value of the check function is passed to another function which then acts appropriately and edits the thing if necessary. Also note, incidentally, that the function you pass to then will be invoked How to pass async function as parameter. But the onClick function on button won't work Parent Component function App() { const [user, setUser] = useState(""); const URL = Skip to main content. httpReq(url). You can't pass in others, you can only emulate it using destructuring or spreads. ). You can use function currying. Data types like functions aren’t serializable and cannot be the resolved value of such a i'd like to pass some arument to the then function properties at their current state when i call my promise. The main logic in index. 16. length, i++) { // run a promise. Then we call f with the arguments we want. 0 How can I access a scope inside a promise in Angularjs? Load 7 more related questions Show fewer related questions When you create a new promise you provide a callback that accepts two parameters both functions resolve and reject respectively. Ask Question Asked 7 years, 10 months ago. – john samcock. getCurrentLocaleAsync(). Viewed 2k times 0 . I need to pass a value i get from a promise where it says **value** in the code. Your are calling functions and passing the resulting promises as arguments to then. You can chain . then((res) => {. async getTemplateHtml() { const data = await this. The code I have works as follows Component 1 function1() { let promise: Promise< any> I cannot convert method 2 into a function because it is used by other functions, in fact I made the parameter resolveFn optional (resolveFn = undefined), You don't return your final result after Promise resolved. In short, promises are asynchroous. The function is of type. This is the code: export default locales = => { var locals; Expo. Arrow functions are always anonymous. Proper Javascript promise construction using finally() 0. then function. Usually the Promise won't resolve instantly, but will perform an async task (e. How can I pass a variable to an async function in another file within a promise? // file1. The function (which will get fired in Vue. The first problem is that Promise. The value is currently 'undefined'. Component<INewTaskEntryProps> { It needs to return a promise that is resolved with the appropriate value when the operation is done. Do not pass it in:. then(function (data) { this. interface INewTaskEntryProps { addTask:any; // this } class NewTaskEntry extends React. const chargeCreditCard = (callback: Function) => { console. Then I am passing a message, but so far no luck putting a function in the message. then() etc. We can store the original function reference, overwrite the function with custom code and call the stored function. How to pass a parameter for a JS function inside . Modified 3 years, 10 months ago. In a class method, I retrieved some data through an async function, this. retrieveData() const html = renderTemplate(`some html template`, {stuff: data} return html } I'm trying to dynamically load properties into a React component. My thought was to create a function that returns a promise, in which the asynchronous event that causes the resolve to be called is the button click. 2. By default, the logger would be console. Pass variables between Promises and functions. Commented Aug 24, 2017 at 9:56 @JeremyThille: He/she probably wants to use the result with Express-style middleware, which will call the function with req, res. retrieveData(). Modified 4 years, 7 months ago. 0. I am wrapping the functions in the express-async-handler to handle the promises returns, strangely if I Actual scenario is i want to return request promise response of test2() from test4() function. then(function([response, i]) { // do something with the response and variable i alert(url Pass variables between Promises and functions. I know I can do a toast. How to pass argument in middle of promise chain? 4. log("before 2 seconds (instantly)") get executed right away (or at all)? Why didn't the second Promise raise an exception when I didn't pass in a function? That would suggest you're wrapping a promise in a promise, which doesn't make any sense. offtopic, but if you don't really care about promise return you can use Promise<any> I have tried a different ways to resolve a promise from an async function so I can do a setstate but they all failed, I have narrowed it down to 3 ways that I have tried which console logs the right information, but when I setstate it fails. Another option is to use Promise. Modified 2 years, 9 months ago. You must put the code that uses your result INSIDE the completion callback function or call some function from within that callback and pass the data as an argument. This approach is intended for fixing things so that the chain can continue. In your first example, you want to push the promises themselves: How to pass data from promise then method to an object method. then() callbacks. all is properly setting foo and bar, however, I can't tell if foo and bar are be Skip to main How to pass a Promise. Passing std::promise object to a function via direct function call. Viewed 1k times 2 . When you do this. You can't resolve a promise with multiple properties just like you can't return multiple values from a function. query(sql);. assert() to test the function calls and Promise values returned. Here is a code sample where we will imagine that getPromise return a number as result : I think it is because the Promise resolve is asynchronous. all to wait for an array of promises to resolve and then act on those. update: I have a situation, where I call a function with some arguments, which are resolved using another function. How to pass a function as parameter to Promise in TypeScript? Ask Question Asked 8 years, 2 months ago. I don't need the specific result from the previous function so I'm not adding anything into resolve(); you are passing a function to . Currying is a process in functional programming in which we can transform a function with multiple arguments into a sequence of nesting functions. In your example you are filling the array immediately before calling Promise. To kick the web worker off, I am passing an object URL (created from a Blob) to the Worker constructor. Commented Jul 23, 2021 at Let’s start today’s tutorial how do you pass parameters to a promise function in javascript? Javascript promise function with parameter example# Here we will create a parameter function and store it in a variable, in the function we will create a promise with a resolve & reject option where we will check if it is greater than 0 resolve Hi I'm new so sorry if my question does not formulate properly. Note, no value is actually returned from either of the function calls, if that matter to the expected result, see Why is value undefined at . query function returns any promise or not. The second problem is [object Promise] Promise object is just the state of waiting for results, but you didn't wait for any results, so that's why it's printed [object Promise] I use async/await for awaiting the final result from your Promise So I made a promise to get that value/property (the ID), and now I need to pass that ID value along to a check function. I am trying to set a few variables from Firebase and then pass those into a anotherfunction. Passing a value between chained Promises in Cloud Functions for Firebase. 5. feed is again going to be a Promise, so I can not pass it to that function. Share I put the two calls in different Promise functions because I want start the job on the lists after the call returned its result. Question: how do I pass this data in the render function. done(function(a,b,c) { onMyUrlLoaded(a, b, c, extraParam); }); There is a shorter syntax for doing this, which consist in using bind. Despite not being very clear what you are doing, answering your core question, this is how you pass a callback function to another function's parameter. Basically, it lies to std::function, then exposes only the parts of std::function that should work. My CustomObject component (below) I have a somedataMap : Map<string, Promise<SomeData>> that I would like to populate. The main issue is that you're only conditionally using the result of the asynchronous operation. js mounted()): I think the Promise API "suggest" to always use them as return values and never as objects that you can access or call. – I am trying to pass an object that I build piece by piece with promises using firebase. const handleLoadedRequest = (resolve, reject) => => { This is the proper solution. getItems(). You could pass a reference to a function to the . this. Your request is a promise so you can simply return that from the imported function and use the eventual returned result of that within the component. js const thisFunc = require('. Ask Question Asked 7 years, 8 months ago. So Promise. retrieving data from a server) first. You can't return value from callback function. There can be lots of different callbacks in that internal array because . Here's a basic example of what I'm trying to do. A promise conceptually represents a value over time so while you can represent composite values you As for passing context down a promise chain please refer to Bergi's excellent canonical on that. How to pass variables through promise chain. you are close to the right answer. DangerZone. Localization. Ask Question Asked 4 years, 10 months ago. I'll insert the code, what it outputs, what I'm having tr Does creating a new Promise add any significant overhead? I'm wanting to wrap all my synchronous Noje. bind I have a series of promise functions that I'm chaining together. then returns work. all() which you can pass an array of promises and it provides an array of responses within the then() callback when all promises passed in have resolved. If you're using await with an asynchronous call inside a Promise callback, just return the asynchronous call -- it's mostly likely it's already returning promise (or else using await in the first place wouldn't make sense). – Bergi. . Function's is executed way before the promise has chance to be resolved. css() method. Ask Question Asked 3 years, 1 month ago. js import React from 'react'; import { connect, I am quite sure that you misunderstand the code snippet in the post. You can assign it to a function with in-turn calls your promise. 2. However the resolution values from the middle of the sequence are not in scope in the last callback, how do I access them? I am trying to pass the data. Get the value of a promise and assign to variable. A slight change allows the directive to pass arguments, which I would think is far more useful. then, or achieve similar behavior? 0. You are not executing it, you are just passing the reference to the function. all() on them all, when Promise. child(postID). Viewed 14k times Asynchronous function used to give the Promise which gives you the data only when it gets fulfilled until then it will show you pending state. Passing an std::shared_future to the std::async(i. Is it possible to send request promise response from AngularJs pass promise response as argument to function. 3. Ask Question Asked 4 years, 7 months ago. the Promise. customObjects using fetch with async/await higher up in the component structure. To demonstrate, consider two proxies for serverCall and myCallback that we know will Your code is not working because you are returning your result from a callback function. So, your function needs to return a promise that is properly hooked up to your asynchronous operation. e. then() and . MouseEventHandler<HTMLButtonElement> I have tried adding the parameters in the Props type function but that only satisfies the function type issues, the onClick type issue still exists and Here we return a new Promise. In the real version, the promise is necessary and contains many other functions. 1. The code snippet is seen in a tutorial. Commented Jul 28, 2017 at 0:59. all anyway. I want to pass a function inside a Promise, then execute that Promise and do something with the result. all and Array#map to wait for all these queries to finish return Promise. all() resolves, then it processes the results however you want and returns that as the resolved value. for error-handling, and in those cases it might be acceptable to pass a promise. Two-part question: Why does console. Thanks Passing data between functions with promise in Node. finally passing to factorial()) is to learn that You have the problem because you are passing the value of isAvailable which is a function. Instead received undefined List. If one or both arguments are omitted or are provided non-functions, then then will be missing the handler(s), but will not generate any errors. Commented Commented May 3, 2017 at 12:37. then() handler you create the object you want in the result that combines source. I'm having some problems with passing parameters through a promise chain I set up. /file2'); Passing data between functions with promise in Node. then() chained to Promise?. Don't ever rely on passing a string as a 'function' when using setTimeout() or setInterval(). set("someId", getSomeData("someId")), then the code in getSomeData is @bluehipy's answer the way to go, though I'd write creatObject like. I settled with passing an array to resolve after a failed attempt to pass more than one arguments. Questions. If you don't want that process to start, don't call axios (etc. You only want to be changing the state of the component from within the component. Your second example returns a different promise, the one created by calling catch. You might want to post your actual code where you decide "what concurrent API calls I need to make at this stage based on the result of a previous API call in According to MDN documentation:. When you call axios (or whatever), it's already started its process that the promise it returns observes. The most elegant solution is to use the Custom Type Formatting supported by the library, which allows you to Promise. done promise callback of a jquery ajax call: promise. How can I pass the variable in es6 promise then callback to the outside. note that using async in your second function is kind of useless, because the function will return a Promise in no time and won't clog the execution whatsoever. You should store the returned value in a variable and try to render it. next() without any arguments. Inside the function, you pass in two arguments: resolve and reject. Here returning vm. Something like : onTick: PromiseRunner where PromiseRunner is the function in which you invoke the promise. In your example, you are always pushing string types into an array. When you call bind in Having assigned promises into a variable may not be a good choice but It is very useful when there is more than one function which returns a promise and we want to execute some code after all promises have resolved. Here is an example code to what I a doing: So if you need to pass arguments to a function, put the expression within an anonymous function body. I am trying to learn JS Promise. You can then run Promise. then() will I mean you create your own function to do what you're asking for. void product(std Uncaught (in promise) TypeError: this. But your answer and from another user gave me better explanation on how to I want to pass a promise as a parameter to another function, use it as a callback. – Ates Goral My question is how can I call getUsers only once (must be called in the useEffect hook like i did since i rely on dependecy array), and use the promise returned as the data prop in InnerComponent? Edit: InnerComponent expects a promise to subscribe to so it can display a different view depending on the promise state (pending, fullfilled, rejected) I have restructured my code to promises, and built a wonderful long flat promise chain, consisting of multiple . Is it correct to return a Promise which returns the responses in I have a scenario where an event hub is receiving data and an Azure function is triggered to fetch the data, I am using promise based npm Http module 'Axios', Pass HTTP request from Azure Function through Event Grid. const myVal = await utility. How to pass promise value into a function. then((value) => { locals = value; }); return locals; } How do i get the promise value and return it on function? @Bergi "What makes you think that store returns a (promise for) the account" Not sure what you mean? The gist of the Answer is that if OP needs to access a value from the previous . The check function should simply return a true/false to see if the ID's match. This will actually take place within a loop so that I can iterate over a form object, passing each key to get an array of associated promises and passing the value to each promise. like this: I am working on creating a simple web application that handles requests and communicates with a SQL db using Express and Sequelize. Use the same approach as with catch. In other words force us to treat them as return values instead of objects we can access or functions we can call or something we can reference with a variable or pass as a parameter, etc. I wrote one simple program to calculate the multiplication of two numbers. Takes a function and returns a new one that will always have a particular context. then() Simply pass resolve and reject to the handleLoadedRequest and handleBadRequest functions. At this point you have an yield at your disposal and you can push your value via gen. You call client. map(function(postSnapshot) { var postID = postSnapshot. launch a function from angular controller with Parameters. If yes then you should do something like this const result = awati con. id with the balance and you return that as the resolved value from the promise. So, to pass an object by reference you need to tell std::async that you're using a reference. I need to pass an extra parameter to the . Passing external variable in function Nodejs. Currently I am running into a problem when calling an async function on an object, the this part of the object is undefined. The critical differences between the two are: In your second example, you're not passing on the resolution value, so the promise returned by your then is resolved with undefined (the return value of console. fetchInfo(); For this to work you have to add async to the function that contains this line: async function funcName(). race, . From the Promises/A+ spec, 2. Also, there's no reason to use Promise. Suppose if you want to get the user one by one by their id and have to store them in the react array state, then chances are there that you might no get the data of all the users. render('graphs', {info: statusChart, vuln: severityChart, count: countChart}); When I try it this way I get the following results on the pug side Pass a promise to a component React Native. Commented May 8, 2018 at 21:08. Synchronous for loop in node js. Use a value from one function in another function. Note that in the other answer the code uses new Function() which has the same security issues than eval – onTick method takes a function only. – vdegenne. When you call . message that I am getting in the fetch call to the success of toastify promise. Plus, you can pass parameters to the function: var some_function = function (username, password) { Essentially, a promise is a returned object to which you attach callbacks, instead of passing callbacks into a function. log("before 2 seconds (instantly)"), which is not a function. I thought about using a state but then I don't think I could call the function inside the ListItem component anymore. then() expects a onFulfilled function, but I passed in console. This function gets a path from javascript and immediately returns a promise,then creates a new thread to load the file, and finally schedules an event that will resolve the promise in the main thread. g. then - whereas in your code, you are passing the result of calling a function to . And if the API is unsuccessful, then you call the reject function by passing any To pass parameters to a promise function with JavaScript, we can create a function that takes the parameters we want to returns the promise. reduce(promisesToExecute, callback is just a parameter name for function that you can pass, 1 . They do not look at how that argument will eventually be used. all accepts an array of promises, not an array of functions - your current code won't work. This solution must be used with caution because of eval. If onFulfilled is a function:. function getArgs (): [string, number] { return ['hello wo Instead the following assigns the promise function to res. I'm trying to use v8 to expose an async "readFile" function to javascript. It is slower, because it has to be evaluated and it just isn't right. map(`${key}`. Javascript passing/chaining a promise using async/await. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company When you obtain the generator you don't have yields you can push value to (you are at the beginning of the generator function). api_props(key) function will return the method ('pos Your other functions will be Promises which resolve or reject their own Promise; that allows for chaining the Promise. Commented Jan 24, 2017 at 14: what if I want to return and export value of vm. I also have an async function async function getSomeData(someIdentifier:string): Promise<SomeData>, that I would like use as the values in that map. I understand how promises work for the most part, but I have a lot of trouble understanding how to deal with them when I need to pass a function as a parameter: var promise = new Promise(function . child Your first example returns the original promise. Here is my promise below . No, the Promises spec only defines the first parameter. The question is: how can I scoped variables to the second . You need to trigger the generator and reach the first yield by calling gen. Please try to discover your mistake by comparing. resolve to enter a state of fulfilled, reject to enter a state of rejected, and if the code your promise wraps throws an exception the promise will also enter a state of rejected. test(req, res, tableName)? – Jeremy Thille. 1, emphasis mine:. then() expects a callback function which will be called when the Promise on which . Here I want to handle / catch the 401 status globally and logout the You could try using Promise. Wrap your Promise inside a function or it will start to do its job right away. How to pass a Promise. So it's not that you don't want to invoke the promises, it's that you don't want to start the things they're observing. then(function(obj ) { Skip to main AngularJs pass promise response as argument to function. Viewed 628 times 0 . then() is adds a callback to an internal array of callbacks. You only have one xhr() promise for each iteration of the loop: // global variable url var url = [url1, url2, url3]; for (i = 0, i < url. parentFunction(email: string, password: string, userName: string): Promise<void> The onClick function is of type. ; The ES6 spec describes this in I tried to return the value from a Promise and assign it to a local variable inside the function, but the Promise gets fired at last. How do I pass the the returned Promise value to another function? I need to retrieve a parsed JSON data and then use that response data to send to Slack channel. then() the returned value from previous . You could also try attaching a local . When passing a Promise from a Server Component to a Client Component, its resolved value must be serializable to pass between server and client. Therefore, not only you can change the context of the function being invoked (you can provide an object instead of this), but you can also pass as many arguments/parameters values as the function receives without Perhaps I am missing something, but although the other solutions do call the parent scope function there is no ability to pass arguments from directive code, this is because the update-fn is calling updateFn() with fixed parameters, in for example {msg: "Hello World"}. jQuery, Firebase,how to reach a variable inside a promise. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company However, when I try to import this function to another file, like so, I can't pass it t because t is not defined: // index. create); An alternative, which may be more easy to understand, and doesn't require a function returning a function - not that there's anything wrong with that, I'd do it like the above, but it can do your head in if you're relatively . Code below shows how to wait for all the promises to resolve and then deal with the results once they are all ready (as that seemed to be the objective of the question); Also for illustrative purposes, it shows output during execution (end finishes before middle). props. Then, you call . transaction(txn => { //lodash reduce function to execute each promise sequentially _. This is how the code looks. because some independent calculation are done in test4() and test2() can not wait for test3() and test4() so i again call test2() from test4() with status flag but the problem is first request promise is overwritten in Memory stack. I wish to run each function in order from 1 to 3, I have found a neat solu @WandersonSilva yes it is a way to do it, you probably know this already, this will be new function, not the exact reference to the original. I am sharing an example code block for you. You can't pass any argument to the onTick How should I type an async function that I'm passing to my React component as a property? My component is defined below. Modified 3 years, 9 months ago. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog The callback that we pass into Promise does something with username and password and call resolve if success is true and reject otherwise to reject the promise. If you're sometimes seeing evidence that the serverCall or myCallback aren't being invoked, then that has something to do with the particulars of those functions, not the ways you are calling them. This is a sample of my react component. query function and then await it. Commented Aug 1, 2017 at 5:40. For instance, we want to add a feature to jQuerys . Oh, dyp's function_mo is rude-- it uses std::function, but stores a hack<F> which contains a F and pretends to be copyable, but said copies simply throw (I think they should std::terminate or just do nothing in practice, so they can state that they don't throw). Improve this answer Problem is, i need to get the promise value and pass it to return function. The getters. OP needs to make sure they are returning the correct value that they are expecting at the reason being useEffect has dependency promise which is a function which contains setTimeOut/ promise and everytime the component renders , a new setTimeout is being pushed to the callbackQueue from the apis section , thereby infinite async and causing re I have a private makeRequest function and public helper functions, like API. var makeCall = function (err, param) { var deferred = Q. Related. This obviously won't work. I have the following function which returns either the sum or difference of two numbers depending on the operation provided by the user. js import { myAsyncFunc } from '. Another way is to assign isAvailable to a lambda expression instead of a function. I am learning the std::promise and std::future in C++. var dummyReq = { client: null }; var dummyUser it doesn't break the chain, the arrow function returns the promise just the original callback function would. /common' myAsyncFunc(t, textA, textB) Is it possible to just pass in my textA and textB arguments (possibly with currying or another way) with async/await? Of course, there are exceptions to every rule, and they would be functions that are explicitly dedicated to handle asynchronous promise logic, like Promise. If the Promise that then is called on adopts a state (fulfillment or rejection) for which then has no handler, a new Promise is created with no additional handlers, simply adopting the final state Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Why don't you just pass it in the function's arguments, like object. 0 Use promise inside resolved promise. Passing value into next Promises argument. ``` <Button onClick={async => await asyncFunc(param1, param2)}/> // even this is ok ``` <Button onClick={() => asyncFunc(param1, param2)}/> ``` ``` But if you do not pass any parameters, passing just your module autoQuote. all waits for an array of Promises. The promise passing kind of works, but I am not sure if this is more than a coincidence. It only happens when i encapsulate the function in that promise the original i psoted above. Stack How to pass promise as a props? Ask Question Asked 3 years, 10 months ago. { // use Promise. In the end I want to return some composite value, and need to access multiple intermediate promise results. next('input1') effectively replacing the On the root question. new Promise(function (resolve, reject) { setTimeout(function { resolve(1) reject(2 Hello this is a question to help me understand how Promises . You can access those array values to pass into functionC:. then(getProductName(companyID)) . const createObject = key => parsed => parsed[key]. As @AlonEitan suggested, you can simplify getSomePromise function: function getSomePromise(myVar) { return new Promise(function (resolve,reject) { if (myVar) resolve("It How to write a callback-based function and then convert it to be a Promise-based function that can be called using async/await. Conclusion. getBalance() and in the . all return to another function Cloud Functions for Firebase. To handle the promise, you need to do it inside the PromiseRunner function using Promise chaining. You're not passing functions to then in your second snippet. It's returning a promise instead of the value which gives me a "failed prop type". The properties are set in this. Check if your . then() can be called more than once on the same promise, each time registering another callback. it must be called after promise is fulfilled, with promise’s value as its first argument. key; return posts. all() is great, but what if you have to pass data from one Promise to another in the chain? For example: (I’m obviously using arbitrary function names here. all() on that array of promises and The code below gives Uncaught Error: You must pass a component to the function returned by connect. all(postSnapshot. Viewed 27k times async function A(B: => Promise<void>) { await B(); } Now I want to call A and pass an async function, then I do it like this: You should also add a . storeData(data); }); I know that here I'm out of scope and this doesn't refer to my Right, like I said, it's informative and I even included this solution in my post (with less detail). I would use the async and await keywords. Modified 8 years, 2 months ago. then() is a method of a promise object. Objective I have three functions that I first get data from a post, Second get my API key and third post data to the API. then(function(res, myMap) { This causes the outer level map to be shadowed, which is why you can't reach it. then passes a value to a callback. However, simply passing a reference won't do that. How to set variable = a value from a I have a function that I would like to pass a value from on to a promise. To pass parameters to a promise function with JavaScript, we can create a function that takes the parameters we want to returns I'm trying to learn using deferred and I'm stumbled as I'm not getting expected arguments in the "then" block. . run() will only be called once during your applications loading. log, but might be replaced by something else, depending on the use case. The body of the Promise calls the resolve method when it is done (in this case that is instantly), triggering the Promise to resolve and execute all then methods chained to the Promise. When resolve() gets called, that causes all the callbacks in the array to get called (after a short delay for the stack to unwind). then, rather than its initial resolve I have something like var test = function(id,companyID) { return getProduct(id) . ) In my project (VUE + Vuex) I need to make some API requests simultaneously, according to some contents and then process the results. I've written a stripped down version for the sake of this example. One way to solve it is as in @Thilo's answer. all method is executed. It will look something like: resolutionFunction(value) You may be wondering, where is resolutionFunction defined? Remember You can not render an async function directly in the JSX because it returns a promise. This is the first Promise call: The then callbacks are getting the value of what you pass to the resolve function in your promises. then chained function? Promises, how to pass variable into . promise method) on the value and expects the returned object to have the respective chainable methods to add listeners. javascript - how to use promises in firebase? 3. I want to define a promise from axios js in a global function. This method returns me the data which I intend to pass it to another function called renderTemplate(). resolve, Promise. target). child('items'). You mess up the std::futures in the aforementioned code snippet, one is a input argument, the other is a return value, they have no relations at all. wwqdgbse tydsc gequ xoqv dzcicr zersh uarokix yzejriye umxfhig xsjqqv