问题描述
我已经启动并运行了节点js服务器,并且我这样处理查询请求:
controller.js
const getUsers = async (req,res,next) => {
const age = req.query.age || 1;
const lessage = req.query.minAge || 1000000000;
const search = req.query.s || '';
let users;
try {
users = await User.find({ age: { $gt: age,$lt: lessage },name: { $regex: search } });
} catch (e) {
console.log('Could not find users : ' + e);
next(e);
}
res.json(users);
};
我检查url中是否有查询值,如果不使用默认值,请在mongoose find()方法中使用该查询值。
现在我的问题是我该如何处理或基本上发送这些查询,以单选按钮,输入和复选框做出反应?我试图在没有任何库的情况下进行处理,并且每次我错过任何东西或陷入错误中。
我尝试过这样:
const what = loc.length < 1 ? '?' : '&';
const [ name,setName ] = React.useState('');
const [ searchName,setSearchName ] = React.useState('');
const [ radio,seTradio ] = React.useState('');
const [ place,setPlace ] = React.useState('');
<select
onChange={(e) => {
setPlace(e.target.value);
setLoc((prev) => prev + place);
}}
>
<option value="">Select place</option>
<option value={`${what}place=us`}>US</option>
<option value={`${what}place=uk`}>UK</option>
</select>
{place}
<form
onChange={(e) => {
seTradio(e.target.value);
setLoc((prev) => prev + radio);
}}
>
<input type="radio" name="gender" value={`${what}age=22`} /> Age over 22 <br />
<input type="radio" name="gender" value={`${what}ageMin=22`} /> Age lower than 22 <br />
</form>
{radio}
<input
type="text"
value={name}
onChange={(e) => {
setName(e.target.value);
}}
/>
没有关于如何在react中发送具有不同选项的多个查询请求的教程或文章。
那么我该如何使用react js处理向后端发送查询请求?
解决方法
我用react useState钩子这样处理查询值的第一个设置值:
const [ name,setName ] = React.useState('');
const [ age,setAge ] = React.useState('');
const [ place,setPlace ] = React.useState('');
<select
onChange={(e) => {
setPlace(e.target.value);
}}
>
<option value="">Select place</option>
<option value="us">US</option>
<option value="uk">UK</option>
</select>
{place}
<br />
<form
onChange={(e) => {
setAge(e.target.value);
}}
>
<input type="radio" name="gender" value="ageMax=22" /> Age over 22 <br />
<input type="radio" name="gender" value="ageMin=22" /> Age lower than 22 <br />
</form>
{age}
<br />
<input
type="text"
value={name}
onChange={(e) => {
setName(e.target.value);
}}
/>
{name}
然后,我为Link的道具提供了这样的条件:
<Link to={handleSearch}>Filter</Link>
const handleSearch = () => {
if (place.length === 0 && name.length === 0) {
return `?${age}`;
}
if (age.length === 0 && name.length === 0) {
return `?place=${place}`;
}
if (age.length === 0 && place.length === 0) {
return `?s=${name}`;
}
if (age.length === 0) {
return `?s=${name}&place=${place}`;
}
if (place.length === 0) {
return `?s=${name}&${age}`;
}
if (name.length === 0) {
return `?${age}&place=${place}`;
}
return `?s=${name}&${age}&place=${place}`;
};