如何检查查询字符串是否具有Express.js/Node.js中的值？

Question

如何检查传递给Express.js应用程序的查询字符串是否包含任何值？如果我有一个API URL,可以是:http://example.com/api/objects或者http://example.com/api/objects?name=itemName,条件语句用于确定我正在处理的是什么？

我当前的代码在下面,它总是评估为'should have no string'选项.

if (req.query !== {}) {
    console.log('should have no query string');
}
else {
    console.log('should have query string');
}

Answer 1

你需要做的就是检查你的钥匙长度Object,像这样,

Object.keys(req.query).length === 0

旁注:你暗示if-else错误的方式,

if (req.query !== {})     // this will run when your req.query is 'NOT EMPTY', i.e it has some query string.

Answer 2

如果要检查是否没有查询字符串，可以进行正则表达式搜索，

if (!/\?.+/.test(req.url) {
    console.log('should have no query string');
}
else {
    console.log('should have query string');
}

如果你正在寻找一个单一的参数试试这个

if (!req.query.name) {
    console.log('should have no query string');
}
else {
    console.log('should have query string');
}