Reactjs 试图设置&;只需单击一个按钮,即可在POST请求中将状态变量作为URL字符串发送
单击时,会取消两个具有自己功能的按钮,一个是savedays,另一个是submitdays。我想结合功能,使它只有一个按钮Reactjs 试图设置&;只需单击一个按钮,即可在POST请求中将状态变量作为URL字符串发送,reactjs,fetch,use-state,Reactjs,Fetch,Use State,单击时,会取消两个具有自己功能的按钮,一个是savedays,另一个是submitdays。我想结合功能,使它只有一个按钮 const [days, setDays] = useState({ Monday: false, Tuesday: false, Wednesday: false, Thursday: false, Friday: false, Saturday: false, Sunday: false, }); co
const [days, setDays] = useState({
Monday: false,
Tuesday: false,
Wednesday: false,
Thursday: false,
Friday: false,
Saturday: false,
Sunday: false,
});
const [selectedDays, setSelectedDays] = useState("");
const saveDays = async () => {
await setSelectedDays((selectedDays) => "");
if (days.Monday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("MON,"));
}
if (days.Tuesday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("TUE,"));
}
if (days.Wednesday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("WED,"));
}
if (days.Thursday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("THUR,"));
}
if (days.Friday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("FRI,"));
}
if (days.Saturday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("SAT,"));
}
if (days.Sunday == true) {
await setSelectedDays((selectedDays) => selectedDays.concat("SUN,"));
}
await setSelectedDays((selectedDays) => selectedDays.slice(0, -1));
console.log(selectedDays, "updated");
};
const submitDays = async () => {
let postRes = await fetch(`/addSurveyDays/${selectedDays}`, {
method: "POST",
headers: {
"Content-Type": "application/json",
Accept: "application/json",
},
});
let postResult = await postRes.json();
if (postResult.success) {
console.log("succes posted");
} else console.log("Something went wrong, please try again");
};
<button
type="button"
className="greyBtn"
id="saveBtn"
onClick={async () => {
await saveDays();
}}
>
Save
</button>
<button
type="button"
className="greyBtn"
id="saveSubmitBtn"
onClick={async () => {
await submitDays();
}}
>
Submit
</button>
const[days,setDays]=useState({
星期一:错,
星期二:错,
星期三:错,
星期四:错,
星期五:错,
星期六:错,
星期日:错,
});
const[selectedDays,setSelectedDays]=useState(“”);
const saveDays=async()=>{
等待设置选定日期((选定日期)=>“”);
如果(days.Monday==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“周一”);
}
如果(天.星期二==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“周二”);
}
如果(天.星期三==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“WED”);
}
如果(天.星期四==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“星期四”);
}
如果(days.Friday==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“FRI”);
}
如果(天.星期六==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“SAT”);
}
如果(days.Sunday==真){
等待设置selectedDays((selectedDays)=>selectedDays.concat(“SUN”);
}
等待设置selectedDays((selectedDays)=>selectedDays.slice(0,-1));
console.log(选择日期,“更新”);
};
const submitDays=async()=>{
让postRes=wait fetch(`/addSurveyDays/${selectedDays}`{
方法:“张贴”,
标题:{
“内容类型”:“应用程序/json”,
接受:“应用程序/json”,
},
});
让postResult=wait postRes.json();
if(postResult.success){
控制台日志(“成功发布”);
}else console.log(“出现问题,请重试”);
};
{
等待保存日();
}}
>
拯救
{
等待提交日期();
}}
>
提交
但是,当我将这两个功能组合在一起时,只需单击一个按钮即可执行。我第一次运行时就出现了这个错误
Chrome控制台日志,“发布HTTP://localhost:3000/addSurveyDays/404(未找到)
错误只有在我第一次运行它时才出现,然后就没问题了。有人能帮我解释一下原因吗
还有7个其他按钮,每个按钮对应于一周中的某一天,单击时打开各自的日期。例如:天。单击其按钮时,星期一将变为真。只需(1)将用于将所选日期字符串构建到单击处理程序中的逻辑添加到(2)触发一个效果,在每次更改selectedDays
状态变量后发送POST请求
const App = () => {
const [days, setDays] = useState({
Monday: false,
Tuesday: false,
Wednesday: false,
Thursday: false,
Friday: false,
Saturday: false,
Sunday: false,
});
const [selectedDays, setSelectedDays] = useState("");
useEffect(async () => {
let postRes = await fetch(`/addSurveyDays/${selectedDays}`, {
method: "POST",
headers: {
"Content-Type": "application/json",
"Accept": "application/json",
},
});
let postResult = postRes.json();
if (postResult.success) {
console.log("succes posted");
} else {
console.log("Something went wrong, please try again");
}
}, [selectedDays]);
const handleSaveAndSubmit = () => {
let newSelectedDays = "";
Object.keys(days).forEach((day) => {
if (days[day]) {
newSelectedDays = newSelectedDays.concat(
day.substring(0, 3).toUpperCase() + ","
);
}
});
console.log(newSelectedDays, "updated");
setSelectedDays(newSelectedDays.slice(0, -1));
};
return (
<button
type="button"
className="greyBtn"
id="saveSubmitBtn"
onClick={handleSaveAndSubmit}
>
Save and Submit
</button>
);
};
const-App=()=>{
const[days,setDays]=useState({
星期一:错,
星期二:错,
星期三:错,
星期四:错,
星期五:错,
星期六:错,
星期日:错,
});
const[selectedDays,setSelectedDays]=useState(“”);
useffect(异步()=>{
让postRes=wait fetch(`/addSurveyDays/${selectedDays}`{
方法:“张贴”,
标题:{
“内容类型”:“应用程序/json”,
“接受”:“应用程序/json”,
},
});
让postResult=postRes.json();
if(postResult.success){
控制台日志(“成功发布”);
}否则{
log(“出现问题,请重试”);
}
},[selectedDays]);
const handleSaveAndSubmit=()=>{
让新闻选择日=”;
Object.key(天).forEach((天)=>{
如果(天[天]){
newSelectedDays=newSelectedDays.concat(
day.substring(0,3).toUpperCase()+“,”
);
}
});
console.log(newSelectedDays,“updated”);
setSelectedDays(newSelectedDays.slice(0,-1));
};
返回(
保存并提交
);
};
错误只有在我第一次运行它时才出现,然后就没问题了。有人能帮我解释一下原因吗 这仅仅是因为您无法从当前范围访问React功能组件中更新的状态变量 在您的情况下,您假设调用
setSelectedDays()
时,selectedDays
会得到更新,并且您可以从当前状态访问更新的值。您不能这样做。等待多长时间无关紧要(请注意,将await
放在状态更新函数前面没有效果,因为它们不是Promise
es)
请参阅:了解更多信息。看起来
所选日期
为空(即“
).在保存日结束时,它将是类似“MON,THUR”的内容。我只是在开始时将其清空以清空字符串。if语句应该添加到字符串中,但似乎不允许共享其余代码?尝试删除不相关的部分。我添加了一些额外信息,让我知道您的想法