需要 JavaScript 中的正则表达式来匹配 '/' 或 '/login'

Question

I need a regex to match either '/' or '/login' at the end of my url. Here is my regex which I am trying.

/\\/(login)?$/.test(window.location.href)

This is what the expected result.

/\/(login)?$/.test('/')             //true
/\/(login)?$/.test('/login')        //true
/\/(login)?$/.test('//')            // false
/\/(login)?$/.test('/login/login')  //false

Basically I want to match exactly one set not multiple.

Answer 1

It would seem that you're testing window.location.href when what you really want is window.location.pathname . You'd then just need anchors at both ends of the RegExp:

/^\/(login)?$/.test(window.location.pathname)

You could attempt something using window.location.href like this:

/^https?:\/\/[^\/]*\/(login)?$/.test(window.location.href)

Problem is it's very fragile, it only needs something like a hash section to break it. It's much safer to let the browser parse the URL for you.

Answer 2

The need to check for preceding repetitions usually implies using lookbehind, here a negative one, which are not available in javascript.
The simpler way to go here is to code a bit:

var test = [ '/', '/login', '//', '/login/login' ];

var reForFail = /(\/(?:login)?)\1$/;
var reForMatch = /\/(?:login)?$/;

console.log(test.map(e => !reForFail.test(e) && reForMatch.test(e)));

You may also have a look at Steven Levithan's mimic-lookbehind-javascript .