要查找数组的实例，请使用:

To find an instance of an array use:

users.find(x => x.username == value);

这将返回 USER 数组中具有匹配用户名的对象.如果它不存在，它将返回 undefined.

This will return the object in the USER array that with the matching user name. It will return undefined if it doesn't exist.

您也可以使用 findIndex，它将返回数组中与谓词匹配的项目的索引，如果不存在则返回 -1:

You can also use findIndex, which will return the index of the item in the array that matches the predicate or -1 if it doesn't exist:

users.findIndex(x => x.username == value);

至于拥有用户名和密码列表，这绝对不是推荐的身份验证.我希望您正在为生产应用程序做其他事情.

As for having a list of usernames and passwords, this is definitely not recommended authentication. I hope you are doing something else for a production application.