Promise then undefined
WebApr 12, 2024 · Teams. Q&A for work. Connect and share knowledge within a single location that is structured and easy to search. Learn more about Teams WebOct 22, 2024 · this参照したい箇所はbindでthisを束縛する。answer内の Promise.bind(this) でやってみる方は解決しなかった。 Typescriptで記述してるときは、 Promise.bind(this) で始めたとしてもメソッドの方は関数型の変数に変えると動いた。
Promise then undefined
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WebApr 10, 2024 · 开发过程中发现前端请求正常执行，接口功能正常且正常返回数据，但是js仍然报语法错误Uncaught (in promise) TypeError: Cannot read properties of undefined … WebAug 23, 2024 · The initial promise resolves in 1 second (*), Then the .then handler is called (**), which in turn creates a new promise (resolved with 2 value). The next then (***) gets the result of the previous one, processes it (doubles) and passes it …
WebMar 14, 2024 · Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'data') 这个错误消息表明在执行代码时发生了一个错误，该错误导致无法读取未定义的属性。. 这通常是因为您尝试访问了一个未定义的变量或对象的属性。. 为了解决这个错误，您需要找出导致错误的 ... WebApr 24, 2024 · 3 Answers. Because you've chained several promises together and one of your .then () handlers returns nothing. .then ( (result) => { console.log ('hello'); // since …
WebPromise 가 이행하거나 거부했을 때, 각각에 해당하는 핸들러 함수 ( onFulfilled 나 onRejected )가 비동기적으로 실행됩니다. 핸들러 함수는 다음 규칙을 따라 실행됩니다. 함수가 값을 반환할 경우, then 에서 반환한 프로미스는 그 반환값을 자신의 결과값으로 하여 이행합니다. 값을 반환하지 않을 경우, then 에서 반환한 프로미스는 undefined 를 결과값으로 하여 … WebOct 20, 2024 · promise .then(undefined) // uses default value => value reaction .then((value) => console.log(value)) I think this happens by accident more than on purpose 🤷♀️ You …
WebMar 30, 2024 · The behavior of the returned promise (call it p) depends on the handler's execution result, following a specific set of rules. If the handler function: returns a value: p …
WebBy definition, a promise is an objectthat encapsulates the result of an asynchronous operation. A promise object has a state that can be one of the following: Pending Fulfilled with a value Rejected for a reason In the beginning, the state of a promise is pending, indicating that the asynchronous operation is in progress. hand exercises print outWebDec 16, 2013 · A promise can only succeed or fail once. It cannot succeed or fail twice, neither can it switch from success to failure or vice versa. If a promise has succeeded or failed and you later add a success/failure callback, the correct callback will be called, even though the event took place earlier. bus glasgow to glencoeWebDec 15, 2024 · Promise states 2. result – This property can have the following values: undefined: Initially when the state value is pending. value: When resolve (value) is called. error: When reject (error) is called. These internal properties are code-inaccessible but they are inspectable. bus gift card holderWebMay 24, 2024 · returnとエラーハンドリング. どのようにreturnするかは、影響が大きいので、きちんと考えて書きます。. 結果としてreturn書かなくても十分な場面は多いですが、returnを考慮した上で、書く、書かないを考えていきたい場所です。. returnの考慮が必須に … bus glasgow to lancasterWebAug 1, 2024 · When the promise is created, its state is set to “pending” and its result is “undefined.” If the request is successful, axios will call its built-in solve() callback to set the promise’s ... hand exercises for finger extensionWebAug 14, 2024 · The promise object returned by the new Promise constructor has these internal properties: state — initially "pending", then changes to either "fulfilled" when resolve is called or "rejected" when reject is called. result — initially undefined, then changes to value when resolve (value) is called or error when reject (error) is called. bus glasgow to lochgilpheadWeb1 day ago · It returns undefined because all of the database stuff hasn't been done yet. It is still fetching the data, etc. You need to wait for the function to finish. It's called promise and the promise either resolves or rejects. So we need to wait for the promise to fulfill. methods.getPunishmentData().then(data => { console.log(data) }) bus glasgow to newtonmore