例如,你可以使用 if 语句来根据条件包含不同的 JSX 代码: let content; if (isLoggedIn) { content = <AdminPanel />; } else { content = <LoginForm />; } return ( {content} ); 如果你喜欢更紧凑的代码,可以使用 ? 条件运算符。与 if 不同,他能与 JSX 语法混合书写: {isLoggedIn ? (...
return; } const sharedQueue = updateQueue.shared; const pending = sharedQueue.pending; if (pending === null) { // This is the first update. Create a circular list. update.next = update; } else { update.next = pending.next; pending.next = update; } sharedQueue.pending = update; } ...
expirationTime);if(root===null){warnAboutUpdateOnUnmountedFiberInDEV(fiber);return;}checkForInterruption(fiber,expirationTime);recordScheduleUpdate();// TODO: computeExpirationForFiber also reads the
Error: Given action "LoadEntries", reducer "entries" returned undefined. To ignore an action, you must explicitly return the previous state. If you want this reducer to hold no value, you can return null instead of undefined. Following is the action file. ...
functioninit(name, options) {validateProjectName(name);if(fs.existsSync(name)) {createAfterConfirmation(name, options); }else{createProject(name, options); } } 可以看到,init方法中实际进行了一些工程名称校验、文件是否存在校验后,最终调用了createProject方法,并将参数传了过去 ...
For example, if user presses left arrow key, key.leftArrow equals true. key.return Type: boolean Default: false Return (Enter) key was pressed. key.escape Type: boolean Default: false Escape key was pressed. key.ctrl Type: boolean Default: false Ctrl key was pressed. key.shift Type: ...
<Else /> Can contain any number of elements inside, which it renders as-is. It can also contain a function. Should not be used outside of an<If />block. It will only be displayed, if parentIfblock's condition is false. A container for<Case condition={...}/>and<Default />blocks...
next(value); if (data.done) { return; } else { data.value.then(x => { value = x; loop(); }) } } loop(); } This function takes any generator as an argument, and keeps calling next() on it as long as there are values to yield. In this case, the yielded values are ...
I am trying to write an error handler, but I get this error: React Hook "useHttpErrorHandler" cannot be called inside a callback. React Hooks must be called in a React function component or a custom React Hook function I don't how else can I handle this errorHandler...
'Fatal:':''}${e.name}${e.message}We will need to restart the app.`,[{text:'Restart',onPress:()=>{RNRestart.Restart();}}]);}else{console.log(e);// So that we can see it in the ADB logs in case of Android if needed}};setJSExceptionHandler(errorHandler);setNativeException...